Chemical solution, method for manufacturing chemical solution, and method for treating substrate

ABSTRACT

A chemical solution, which demonstrates excellent etching performance for transition metal-containing substances and has excellent defect inhibition performance, a method for manufacturing the chemical solution, and a method for treating a substrate. The chemical solution according to an embodiment includes one or more kinds of periodic acids selected from the group consisting of a periodic acid and a salt thereof, one or more kinds of first metal components selected from the group consisting of Ti and Zr, and water. In a case where the chemical solution includes one kind of first metal component, a content of the one kind of first metal component is 1 ppt by mass to 100 ppm by mass with respect to a total mass of the periodic acids. In a case where the chemical solution includes two kinds of first metal components, a content of both the two kinds of first metal components is equal to or smaller than 100 ppm by mass with respect to the total mass of the periodic acids, and a content of at least one of the two kinds of first metal components is equal to or greater than 1 ppt by mass with respect to the total mass of the periodic acids.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. application Ser.No. 16/940,515 filed on Jul. 28, 2020, which is a Continuation of PCTInternational Application No. PCT/JP2019/001452 filed on Jan. 18, 2019,which claims priority under 35 U.S.C. § 119(a) to Japanese PatentApplication No. 2018-018459 filed on Feb. 5, 2018 and Japanese PatentApplication No. 2018-160719 filed on Aug. 29, 2018. Each of the aboveapplications is hereby expressly incorporated by reference, in itsentirety, into the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a chemical solution, a method formanufacturing a chemical solution, and a method for treating asubstrate.

2. Description of the Related Art

As the miniaturization of semiconductor products progresses, there is anincreasing demand for performing a step of removing unnecessarytransition metal-containing substances on a substrate in a semiconductorproduct manufacturing process with high efficiency and high accuracy.

JP2016-092101A describes “method for treating a substrate on which aruthenium-containing film is formed, including a step of removingruthenium deposits attached to the outer edge portion of a surface ofthe substrate on which the ruthenium-containing film is formed and/orruthenium deposits attached to a back surface of the substrate by usinga remover solution, wherein a content of orthoperiodic acid in theremover solution with respect to a total mass of the remover solution is0.05% to 8% by mass, and a pH of the remover solution is equal to orlower than 3.5 (claim 1)”.

SUMMARY OF THE INVENTION

In recent years, it has been increasingly required that excellentetching performance is demonstrated in a case where unnecessarytransition metal-containing substances on a substrate are removed usinga chemical solution. Particularly, it has been required that excellentetching performance is demonstrated for an object to be treatedincluding ruthenium (Ru).

Furthermore, it has been required that in a case where a chemicalsolution is used, the occurrence of defects on a substrate for which thechemical solution is used is further inhibited. In a case where defectsoccur on a substrate, an electrical fault tends to occur between wiringsarranged on the substrate, which leads to a decrease in yield.

Therefore, an object of the present invention is to provide a chemicalsolution which demonstrates excellent etching performance for transitionmetal-containing substances and has excellent defect inhibitionperformance.

Another object of the present invention is to provide a method formanufacturing the chemical solution and a method for treating asubstrate.

In order to achieve the above objects, the inventors of the presentinvention conducted intensive examinations. As a result, the inventorshave found that by a predetermined chemical solution, the above objectscan be achieved, and have accomplished the present invention.

That is, the inventors have found that the above objects can be achievedby the following constitution.

[1] A chemical solution including one or more kinds of periodic acidsselected from the group consisting of a periodic acid and a saltthereof,

-   -   one or more kinds of first metal components selected from the        group consisting of Ti and Zr, and    -   water,    -   in which in a case where the chemical solution includes one kind        of first metal component, a content of the one kind of first        metal component is 1 ppt by mass to 100 ppm by mass with respect        to a total mass of the periodic acids, and    -   in a case where the chemical solution includes two kinds of        first metal components, a content of both the two kinds of first        metal components is equal to or smaller than 100 ppm by mass        with respect to the total mass of the periodic acids, and a        content of at least one of the two kinds of first metal        components is equal to or greater than 1 ppt by mass with        respect to the total mass of the periodic acids.

[2] The chemical solution described in [1], in which in a case where thechemical solution includes one kind of first metal component, a contentof the one kind of first metal component is 1 ppb by mass to 100 ppb bymass with respect to the total mass of the periodic acids, and

-   -   in a case where the chemical solution includes two kinds of        first metal components, a content both the two kinds of first        metal components is equal to or smaller than 100 ppb by mass        with respect to the total mass of the periodic acids, and a        content of at least one of the two kinds of first metal        components is equal to or greater than 1 ppb by mass with        respect to the total mass of the periodic acids.

[3] The chemical solution described in [1] or [2], further including apH adjuster. [4] The chemical solution described in any one of [1] to[3] that has a pH of 4.0 to 9.0. [5] The chemical solution described inany one of [1] to [3] that has a pH of 7.5 to 10.0. [6] The chemicalsolution described in any one of [1] to [5], in which a content of theperiodic acids with respect to a total mass of the chemical solution is0.0001% to 50% by mass.

[7] The chemical solution described in any one of [1] to [6], furtherincluding one or more kinds of second metal components selected from thegroup consisting of Al, Ag, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg,Mn, Na, Ni, Pb, Ru, Sn, and Zn,

-   -   in which in a case where the chemical solution includes one kind        of second metal component, a content of the one kind of second        metal component is 1 ppt by mass to 100 ppm by mass with respect        to the total mass of the periodic acids, and    -   in a case where the chemical solution includes two or more kinds        of second metal components, a content of all of the two or more        kinds of second metal components is equal to or smaller than 100        ppm by mass with respect to the total mass of the periodic        acids, and a content of at least one of the two or more kinds of        second metal components is equal to or greater than 1 ppt by        mass with respect to the total mass of the periodic acids.

[8] The chemical solution described in any one of [1] to [7], furtherincluding ammonium ions, in which a content of the ammonium ions is 1ppt by mass to 100 ppm by mass with respect to the total mass of theperiodic acids.

[9] The chemical solution described in any one of [1] to [8], furtherincluding one or more kinds of anionic species selected from the groupconsisting of I⁻, I₃ ⁻, IO₃ ⁻, Br, Cl⁻, NO₃ ⁻, a sulfate ion, a sulfiteion, a phosphate ion, and a phosphite ion,

-   -   in which in a case where the chemical solution includes one kind        of anionic species, a content of the one kind of anionic species        is 1 ppt by mass to 100 ppm by mass with respect to the total        mass of the periodic acids, and    -   in a case where the chemical solution includes two or more kinds        of anionic species, a content of all of the two or more kinds of        anionic species is equal to or smaller than 100 ppm by mass with        respect to the total mass of the periodic acids, and a content        of at least one of the two or more kinds of anionic species is        equal to or greater than 1 ppt by mass with respect to the total        mass of the periodic acids.

[10] The chemical solution described in [9], in which the anionicspecies is IO₃ ⁻.

[11] A method for manufacturing a chemical solution, including a step Aof performing an ion exchange method on a substance to be purified,which includes one or more kinds of periodic acids selected from thegroup consisting of a periodic acid and a salt thereof, one or morekinds of first metal components selected from the group consisting of Tiand Zr, and water, so as to obtain the chemical solution described inany one of [1] to [10].

[12] The method for manufacturing a chemical solution described in [11],in which the ion exchange method includes one or more kinds of methodsselected from the group consisting of

-   -   a method A1 of passing the substance to be purified through a        first filled portion filled with a mixed resin including a        cation exchange resin and an anion exchange resin,    -   a method A2 of passing the substance to be purified through at        least one kind of filled portion among a second filled portion        filled with a cation exchange resin, a third filled portion        filled with an anion exchange resin, and a fourth filled portion        filled with a chelating resin, and    -   a method A3 of passing the substance to be purified through a        membranous ion exchanger.

[13] The method for manufacturing a chemical solution described in [12],in which the method A1 is a method of passing the substance to bepurified through two or more of the first filled portions.

[14] The method for manufacturing a chemical solution described in [12]or [13], in which the method A2 is a method of passing the substance tobe purified through two or more of the second filled portions and two ormore of the third filled portions, or

-   -   a method of passing the substance to be purified through one or        more of the second filled portions and one or more of the fourth        filled portions.

[15] The method for manufacturing a chemical solution described in anyone of [12] to [14], in which the method A3 is a method of passing thesubstance to be purified through two or more membranous ion exchangers.

[16] The method for manufacturing a chemical solution described in anyone of [12] to [15], in which the ion exchange method includes two ormore kinds of methods selected from the group consisting of the methodA1, the method A2, and the method A3.

[17] The method for manufacturing a chemical solution described in anyone of [11] to [16], further including a step B of filtering thesubstance to be purified having undergone the step A by using a filterafter the step A.

[18] The method for manufacturing a chemical solution described in anyone of [11] to [17], further including a step C of mixing the substanceto be purified with a pH adjuster before the step A.

[19] A method for treating a substrate, including a step D of removing atransition metal-containing substance on a substrate by using thechemical solution described in any one of [1] to [10].

[20] The method for treating a substrate described in [19], in which inthe step D, two or more kinds of transition metal-containing substanceson the substrate are simultaneously removed.

[21] The method for treating a substrate described in [20], in which thetwo or more kinds of transition metal-containing substances include atleast a Ru-containing substance and a Cu-containing substance.

[22] The method for treating a substrate described in any one of [19] to[21], further including performing a rinsing treatment on the substrateobtained by the step D by using a rinsing solution after the step D.

[23] The method for treating a substrate described in [22], in which therinsing solution is an acidic rinsing solution.

According to the present invention, it is possible to provide a chemicalsolution which demonstrates excellent etching performance for transitionmetal-containing substances and has excellent defect inhibitionperformance.

Furthermore, according to the present invention, it is possible toprovide a method for manufacturing the chemical solution and a methodfor treating a substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional top view showing an example of anobject to be treated used in a step D1.

FIG. 2 is a schematic cross-sectional top view showing an example of anobject to be treated having undergone the step D1.

FIG. 3 is a schematic view showing an example of an object to be treatedused in a step D2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be specifically described.

The following constituents will be described based on typicalembodiments of the present invention in some cases, but the presentinvention is not limited to the embodiments.

In the present specification, in a case where there is no descriptionregarding whether a group (atomic group) is substituent orunsubstituted, as long as the effects of the present invention are notreduced, the group includes both the group having no substituent and thegroup having a substituent. For example, “alkyl group” includes not onlyan alkyl group having no substituent (unsubstituted alkyl group) butalso an alkyl group having a substituent (substituted alkyl group). Thesame is true of each compound.

In the present specification, “preparation” means not only thepreparation of a specific material by means of synthesis or mixing butalso the preparation of a predetermined substance by means of purchaseand the like.

In the present specification, “ppm” means “parts-per-million (10⁻⁶)”,“ppb” means “parts-per-billion (10⁻⁹)”, and “ppt” means“parts-per-trillion (10⁻¹²)”.

In the present invention, 1 Å (angstrom) equals 0.1 nm.

[Chemical Solution]

The chemical solution according to an embodiment of the presentinvention includes one or more kinds of periodic acids selected from thegroup consisting of periodic acid and a salt thereof, one or more kindsof first metal components selected from the group consisting of Ti andZr, and water, in which the amount of the first metal components iswithin a predetermined range.

The mechanism through which the objects of the present invention areachieved by the chemical solution constituted as above is unclear.According to the inventors of the present invention, the mechanism isassumed to be as follows.

The inventors of the present invention assume that in a case where apredetermined amount of periodic acids act as a main dissolver liquid inan etching solution for a transition metal-containing substance, and theetching solution includes at least one of the first metal components inan amount equal to or greater than a predetermined amount, the firstmetal component included in an amount equal to or greater than apredetermined amount may play as a catalyst, and thus excellent etchingperformance of the chemical solution may be realized.

The inventors of the present invention assume that meanwhile, becausethe content of the first metal component in the chemical solutionaccording to the embodiment of the present invention is equal to orsmaller than a predetermined amount, metal atoms of the first metalcomponent and the like may hardly remain on an object to be treated thathas been treated using the chemical solution, and thus the occurrence ofdefects could be inhibited. In a case where the occurrence of defects isinhibited as described above, even though the chemical solutionaccording to the embodiment of the present invention is used formanufacturing a wiring substrate, an electrical fault such as theelectrical conduction between wiring hardly occurs on the wiringsubstrate, and the manufacturing yield of the wiring substrate isimproved.

<One or More Kinds of Periodic Acids Selected from Group Consisting ofPeriodic Acid and Salt Thereof>

The chemical solution according to the embodiment of the presentinvention includes one or more kinds of periodic acids selected from thegroup consisting of a periodic acid and a salt thereof (salt of aperiodic acid).

As the periodic acids, one or more kinds of compounds selected from thegroup consisting of orthoperiodic acid (H₅IO₆), a salt of orthoperiodicacid, metaperiodic acid (HIO₄), and a salt of metaperiodic acid salt arepreferable. Among these, orthoperiodic acid is preferable because itdoes not include an alkali metal such as sodium (Na⁺) and thecomposition thereof is stable.

In view of excellent etching performance of the chemical solution, thecontent (total content) of the periodic acids with respect to the totalmass of the chemical solution is preferably 0.0001% to 50% by mass, morepreferably 1% to 45% by mass, even more preferably 2% to 40% by mass,and particularly preferably 4% to 40% by mass.

The concentration of the periodic acids in the chemical solution ismeasured, for example, by ion chromatography. Specifically, examples ofthe device include Dionex ICS-2100 manufactured by Thermo FisherScientific Inc.

In addition, in a case where the components of the used raw materialsare known, the concentration of the periodic acids may be calculatedfrom the amount thereof mixed together.

<One or More Kinds of First Metal Components Selected from GroupConsisting of Ti and Zr>

The chemical solution according to the embodiment of the presentinvention includes one or more kinds of first metal components selectedfrom the group consisting of Ti and Zr. As will be specificallydescribed later, the first metal component may be separately added atthe time of preparing the chemical solution according to the embodimentof the present invention. In some cases, the first metal component maybe incorporated as a minor component into the raw materials of theperiodic acids. In these cases, as will be described later, the contentof the first metal component can be reduced by an ion exchange methodand adjusted to fall into a predetermined range. Presumably, as thereason why the first metal component is mixed into the raw materials ofthe periodic acids, it is possible to consider a case where the firstmetal component is used as a catalyst at the time of synthesizing theperiodic acids and then remains as it is, a case where the componentattached to piping is mixed into the raw materials of the periodic acidsduring the manufacturing process of the periodic acids, and the like.

In the present specification, “first metal component” means a metalcomponent in a chemical solution that can be measured using asingle-particle inductively coupled plasma emission mass spectrometer.By the above device, the content of each of the metals as particles(metals in the form of particles) and other metals (for example, ionsand the like) and the total content of these can be measured. That is,the first metal component may be in the form of particles or in an ionicstate.

In the present specification, the metal components (the first metalcomponent and the second metal component which will be described later)can be measured by the method described in Examples by using, forexample, Agilent 8800 triple quadrupole inductively coupled plasma massspectrometry (ICP-MS, for semiconductor analysis, option #200)manufactured by Agilent Technologies, Inc.

In a case where the chemical solution includes one kind of first metalcomponent, the content of the one kind of first metal component is 1 pptby mass to 100 ppm by mass with respect to the total mass of theperiodic acids. That is, in a case where the chemical solution includeseither Ti or Zr as the first metal component, the content of the firstmetal component is 1 ppt by mass to 100 ppm by mass (preferably 1 ppb bymass to 100 ppb by mass) with respect to the total mass of the periodicacids.

Particularly, in view of further improving the etching performance ofthe chemical solution, the content is preferably equal to or greaterthan 1 ppb by mass. Furthermore, in view of further improving the defectinhibition performance of the chemical solution, the content ispreferably equal to or smaller than 100 ppb by mass, more preferablyequal to or smaller than 10 ppb by mass, and even more preferably equalto or smaller than 5 ppb by mass.

In a case where the chemical solution includes two kinds of first metalcomponents (Ti and Zr), the content of the two kinds of first metalcomponents (the content of both the two kinds of first metal components)is equal to or smaller than 100 ppm by mass with respect to the totalmass of the periodic acids. Particularly, in view of further improvingthe defect inhibition performance of the chemical solution, the contentof both the two kinds of first metal components is preferably equal toor smaller than 100 ppb by mass, more preferably equal to or smallerthan 10 ppb by mass, and even more preferably equal to or smaller than 5ppb by mass.

In a case where the chemical solution includes two kinds of first metalcomponents (Ti and Zr), the content of at least one of the two kinds offirst metal components (content of one kind of first metal componentbetween the two kinds of first metal components) is equal to or greaterthan 1 ppt by mass with respect to the total mass of the periodic acids.Particularly, in view of further improving the etching performance ofthe chemical solution, the content of at least one of the two kinds offirst metal components is preferably equal to or greater than 1 ppb bymass.

As described above, in a case where the chemical solution includes twokinds of first metal components (Ti and Zr), the content of at least oneof the two kinds of first metal components may be equal to or greaterthan 1 ppt by mass. In other words, in a case where the chemicalsolution includes two kinds of first metal components (Ti and Zr), thecontent of one of the two kinds of first metal components may be equalto or greater than 1 ppt by mass and equal to or smaller than 100 ppm bymass with respect to the total mass of the periodic acids, and thecontent of the other kind of first metal component may be greater than 0ppt by mass and equal to or smaller than 100 ppm by mass (preferablyequal to or greater than 0.1 ppt by mass and equal to or smaller than100 ppm by mass).

In a case where the chemical solution includes two kinds of first metalcomponents (Ti and Zr), in view of further improving the etchingperformance of the chemical solution, the content of the two kinds offirst metal components (the content of both the two kinds of first metalcomponents) with respect to the total mass of the periodic acids ispreferably equal to or greater than 1 ppt by mass, and more preferablyequal to or greater than 1 ppb by mass.

<Water>

The Chemical Solution Includes Water.

Water may include a trace of components that are unavoidably mixed in.Particularly, water having undergone a purification treatment such asdistilled water, deionized water, or ultrapure water is preferable, andultrapure water used for manufacturing semiconductors is morepreferable.

The concentration of water in the chemical solution is not particularlylimited, but is preferably equal to or higher than 40% by mass, morepreferably equal to or higher than 50% by mass, and even more preferablyequal to or higher than 60% by mass. The upper limit thereof is notparticularly limited, but is preferably equal to or lower than 99.95% bymass, more preferably equal to or lower than 99% by mass, and even morepreferably equal to or lower than 95% by mass.

<Optional Components>

The chemical solution may include other optional components in additionto the components described above. Hereinafter, the optional componentswill be described.

(pH Adjuster)

The chemical solution according to the embodiment of the presentinvention may include a pH adjuster.

Examples of the pH adjuster include an organic base, an inorganic base,an organic acid, and an inorganic acid. Among these, an organic base oran inorganic base is preferable, and an organic base is more preferable.

Specific examples of the pH adjuster include a quaternary ammonium saltcompound, an amidine compound, and a water-soluble amine.

As the quaternary ammonium salt compound, a compound represented byFormula (1) is preferable.

In Formula (1), R^(4A) to R^(4D) each independently represent an alkylgroup having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6carbon atoms, a benzyl group, or an aryl group.

In Formula (1), R^(4A) to R^(4D) each independently represent an alkylgroup having 1 to 6 carbon atoms (for example, a methyl group, an ethylgroup, a butyl group, or the like), a hydroxyalkyl group having 1 to 6carbon atoms (for example, a hydroxymethyl group, a hydroxyethyl group,a hydroxybutyl group, or the like), a benzyl group, or an aryl group(for example, a phenyl group, a naphthyl group, a naphthalene group, orthe like). Among these, an alkyl group, a hydroxyethyl group, or abenzyl group is preferable.

As the compound represented by Formula (1), at least one kind ofquaternary ammonium hydroxide salt is preferable which is selected fromthe group consisting of tetramethylammonium hydroxide (TMAH),tetraethylammonium hydroxide (TEAH), tetrabutylammonium hydroxide(TBAH), trimethylhydroxyethylammonium hydroxide,methyltri(hydroxyethyl)ammonium hydroxide, tetra(hydroxyethyl)ammoniumhydroxide, trimethylbenzylammonium hydroxide, and choline. Among these,as the compound represented by Formula (1), at least one kind ofcompound is more preferable which is selected from the group consistingof tetramethylammonium hydroxide, tetraethylammonium hydroxide, andtetrabutylammonium hydroxide.

One kind of quaternary ammonium salt compound may be used singly, or twoor more kinds of quaternary ammonium salt compounds may be used.

Examples of the amidine compound include acetamidine, imidazotan,2-methylimidazole, 1,4,5,6-tetrahydropyrimidine,2-methyl-1,4,5,6-tetrahydropyrimidine,2-phenyl-1,4,5,6-tetrahydropyrimidine, iminopiperidine,diazabicyclononene, diazabicycloundecene (DBU), and the like. Amongthese, diazabicycloundecene is preferable.

A pka of the water-soluble amine is preferably 7.5 to 13.0. In thepresent specification, the water-soluble amine means an amine which candissolve in an amount equal to or greater than 1.0 g in 1 L of water.Aqueous ammonia is not included in the water-soluble amine.

Examples of the water-soluble amine having a pKa of 7.5 to 13 includediglycolamine (DGA) (pKa=9.80), methylamine (pKa=10.6), ethylamine(pKa=10.6), propylamine (pKa=10.6), butylamine (pKa=10.6), pentylamine(pKa=10.0), ethanolamine (pKa=9.3), propanolamine (pKa=9.3), butanolamine (pKa=9.3), methoxyethylamine (pKa=10.0), methoxypropylamine(pKa=10.0), dimethylamine (pKa=10.8), diethylamine (pKa=10.9), diaminepropylamine (pKa=10.8), trimethylamine (pKa=9.80), and triethylamine(pKa=10.72).

As the water-soluble amine, unsubstituted hydroxylamine and ahydroxylamine derivative may also be used.

In the present specification, the pka of the water-soluble amine is anacid dissociation constant in water. The acid dissociation constant inwater can be measured using a spectrometer and potentiometry incombination.

Among these, as a pH adjuster, tetramethylammonium hydroxide,tetraethylammonium hydroxide, tetrabutylammonium hydroxide, ordiazabicycloundecene is preferable.

(Second Metal Component)

The chemical solution may include a metal component other than the firstmetal component.

The chemical solution may include one or more kinds of second metalcomponents selected from the group consisting of Al, Ag, B, Ba, Ca, Cd,Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Ru, Sn, and Zn.

In some cases, boron (B) is classified as a semimetal. However, in thepresent specification, boron is regarded as a metal.

In the present specification, “second metal component” means a metalcomponent in a chemical solution that can be measured using asingle-particle inductively coupled plasma emission mass spectrometer.By the above device, the content of each of the metals as particles(metals in the form of particles) and other metals (for example, ionsand the like) and the total content of these can be measured. That is,the second metal component may be in the form of particles or in anionic state.

In a case where the chemical solution includes one kind of second metalcomponent, the content of the one kind of second metal component ispreferably 1 ppt by mass to 100 ppm by mass (more preferably 1 ppb bymass to 100 ppb by mass) with respect to the total mass of the periodicacids.

In a case where the chemical solution includes two or more kinds ofsecond metal components, the content of all of the two or more kinds ofsecond metal components is equal to or smaller than 100 ppm by mass(more preferably equal to or smaller than 100 ppb by mass) with respectto the total mass of the periodic acids, and the content of at least oneof the two or more kinds of second metal components is equal to orgreater than 1 ppt by mass (more preferably equal to or greater than 1ppb by mass) with respect to the total mass of the periodic acids.

In other words, in a case where the chemical solution includes two ormore kinds of second metal components, at least one of the two or morekinds of second metal components is preferably equal to or greater than1 ppt by mass and equal to or smaller than 100 ppm by mass with respectto the total mass of the periodic acids, and the content of other secondmetal components among the two or more kinds of second metal componentsis preferably greater than 0 ppt by mass and equal to or smaller than100 ppm by mass (more preferably equal to or greater than 0.1 ppt bymass and equal to or smaller than 100 ppm by mass).

Furthermore, in a case where the chemical solution includes two or morekinds of second metal components, the content of all of the two or morekinds of second metal components with respect to the total mass of theperiodic acids is preferably equal to or greater than 1 ppt by mass, andmore preferably equal to or greater than 1 ppb by mass.

(Ammonium Ions)

In view of further improving the etching performance, the chemicalsolution may include ammonium ions (NH₄ ⁺).

The content of the ammonium ions with respect to the total mass of theperiodic acids is, for example, preferably 1 ppt by mass to 100 ppm bymass, and more preferably 1 ppb by mass to 1 ppm by mass.

(Anionic Species)

In view of improving the smoothness (roughness) of a portion to betreated, the chemical solution may include one or more kinds of anionicspecies selected from the group consisting of I⁻, I₃ ⁻, IO₃ ⁻, Br, Cl⁻,NO₃ ⁻, a sulfate ion, a sulfite ion, a phosphate ion, and a phosphiteion. As the anionic species, IO₃ ⁻ is preferable.

In a case where the chemical solution includes one kind of anionicspecies, the content of the one kind of anionic species is preferably 1ppt by mass to 100 ppm by mass (more preferably 1 ppb by mass to 1 ppmby mass) with respect to the total mass of the periodic acids.

In a case where the chemical solution includes two or more kinds ofanionic species, the content of all of the two or more kinds of anionicspecies is equal to or smaller than 100 ppm by mass (more preferablyequal to or smaller than 1 ppm by mass) with respect to the total massof the periodic acids, and the content of at least one of the two ormore kinds of anionic species is equal to or greater than 1 ppt by mass(more preferably equal to or greater than 1 ppb by mass) with respect tothe total mass of the periodic acids.

In other words, in a case where the chemical solution includes two ormore kinds of anionic species, the content of at least one of the two ormore kinds of anionic species is preferably equal to or greater than 1ppt by mass and equal to or smaller than 100 ppm by mass with respect tothe total mass of the periodic acids, and the content of all of otheranionic species among the two or more kinds of anionic species ispreferably greater than 0 ppt by mass and equal to or smaller than 100ppm by mass (more preferably equal to or greater than 0.1 ppt by massand equal to or smaller than 100 ppm by mass).

Furthermore, in a case where the chemical solution includes two or morekinds of anionic species, the content of all of the two or more kinds ofanionic species with respect to the total mass of the periodic acids ispreferably equal to or greater than 1 ppt by mass, and more preferablyequal to or greater than 1 ppb by mass.

Particularly, the chemical solution preferably includes IO₃ ⁻ as theanionic species, and the content of IO₃ ⁻ in the chemical solution ispreferably 1 ppt by mass to 100 ppm by mass (more preferably 1 ppb bymass to 1 ppm by mass) with respect to the total mass of the periodicacids.

The content of the ammonium ions and the anionic species can bedetermined, for example, by ion chromatography.

Specifically, examples of the device include Dionex ICS-2100manufactured by Thermo Fisher Scientific Inc.

In addition, in a case where the components of the used raw materialsare known, the concentration of the periodic acids may be calculatedfrom the amount thereof mixed together.

(Carboxylic acid compound)

It is also preferable that the chemical solution according to theembodiment of the present invention further includes a carboxylic acidcompound.

The carboxylic acid compound is a compound having one or more carboxygroups or a salt thereof.

The carboxylic acid compound acts as an agent for improving the residueremovability of the chemical solution, a flatness enhancer, and thelike.

The carboxylic acid compound effectively prevents the corrosion ofmetals such as aluminum, copper, and alloys of these.

It is also preferable that the carboxylic acid compound acts as achelating agent that exerts a chelating effect on metals (for example,aluminum, copper, and alloys of these).

As the carboxylic acid compound (preferably, a carboxylic acid compoundacting as a chelating agent) included in the chemical solution accordingto the embodiment of the present invention, a carboxylic acid compoundhaving no nitrogen atom is particularly preferable.

Examples of the carboxylic acid compound having no nitrogen atom includecitric acid, lactic acid, acetic acid, propionic acid, malic acid,tartaric acid, malonic acid, oxalic acid, succinic acid, gluconic acid,glycolic acid, diglycolic acid, maleic acid, benzoic acid, phthalicacid, salicylic acid, salicylhydroxamic acid, phthalhydroxamic acid,formic acid, and salts of these.

Among these, citric acid, lactic acid, acetic acid, malic acid, tartaricacid, malonic acid, oxalic acid, glycolic acid, phthalic acid,salicylhydroxamic acid, or phthalhydroxamic acid is preferable.

Examples of carboxylic acid compounds having a nitrogen atom includediethylene triamine pentaacetic acid (DTPA).

One kind of carboxylic acid compound may be used singly, or two or morekinds of carboxylic acid compounds may be used.

In a case where the chemical solution according to the embodiment of thepresent invention contains a carboxylic acid compound, in view ofpreventing the corrosion of a transition metal-containing substance (forexample, copper) to be treated or improving flatness, the content of thecarboxylic acid compound with respect to the total mass of the chemicalsolution is preferably 0.001% to 10% by mass, more preferably 0.01% to5% by mass, and even more preferably 0.01% to 3% by mass.

(Other Chelating Agents)

The chemical solution according to the embodiment of the presentinvention may include a chelating agent other than the carboxylic acidcompound.

(Water-soluble organic solvent)

It is also preferable that the chemical solution according to theembodiment of the present invention includes a water-soluble organicsolvent.

The water-soluble organic solvent is preferable in view of preventingthe corrosion of a transition metal-containing substance (for example,copper) to be treated or improving flatness.

Examples of the water-soluble organic solvent include alcohol-basedsolvents such as methyl alcohol, ethyl alcohol, 1-propyl alcohol,2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol,glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol,2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol;ether-based solvents such as ethylene glycol monomethyl ether,diethylene glycol, dipropylene glycol, propylene glycol monomethylether, diethylene glycol Monomethyl ether, triethylene glycol,polyethylene glycol, propylene glycol monomethyl ether, dipropyleneglycol monomethyl ether, tripropylene glycol monomethyl ether,diethylene glycol monobutyl ether, diethylene glycol diethyl ether(DEGDEE), and diethylene glycol monobutyl ether; amide-based solventssuch as formamide, monomethylformamide, dimethylformamide, acetamide,monomethylacetamide, dimethylacetamide, monoethylacetamide, diethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such asdimethyl sulfone, dimethyl sulfoxide, and sulfolane; lactone-basedsolvents such as γ-butyrolactone and δ-valerolactone, and the like.

As the water-soluble organic solvent, among these, the alcohol-basedsolvents or the ether-based solvents are preferable, and diethyleneglycol diethyl ether, 1,6-hexanediol, diethylene glycol, propyleneglycol, dipropylene glycol, propylene glycol monomethyl ether, ordipropylene glycol monomethyl ether is more preferable.

One kind of water-soluble organic solvent may be used singly, or two ormore kinds of water-soluble organic solvents may be used.

In a case where the chemical solution includes a water-soluble organicsolvent, the content of the water-soluble organic solvent with respectto the total mass of the chemical solution is preferably greater than 0%by mass and equal to or smaller than 90% by mass, more preferablygreater than 0% by mass and equal to or smaller than 40% by mass, andeven more preferably 0.01% to 15% by mass.

(Other Components)

The chemical solution according to the embodiment of the presentinvention may include other components in addition to the componentsdescribed above.

Those other components are not particularly limited, and examplesthereof include known components. Examples of the components include thesurfactants described in paragraph “0026” of JP2014-093407A, paragraphs“0024” to “0027” of JP2013-055087A, paragraphs “0024” to “0027” ofJP2013-012614A, and the like.

Examples thereof also include the additives (anticorrosive and the like)described in paragraphs “0017” to “0038” of JP2014-107434A, paragraphs“0033” to “0047” of JP2014-103179A, paragraphs “0017” to “0049” ofJP2014-093407A, and the like.

<pH>

The pH of the chemical solution according to the embodiment of thepresent invention is not particularly limited. Particularly, the pH ofthe chemical solution is preferably 3.0 to 10.0.

Particularly, in view of further improving the etching performance for atransition metal-containing substance, the pH of the chemical solutionis more preferably 4.0 to 9.0.

Furthermore, in a case where two or more kinds of transitionmetal-containing substances need to be removed using the chemicalsolution or the like, in view of further improving the balance betweenthe etching performance and the surface properties (smoothness and thelike) of a portion to be treated, the pH of the chemical solution ismore preferably 7.5 to 10.0.

That is, in a case where the chemical solution includes a pH adjuster,the content of the pH adjuster with respect to the total mass of thechemical solution is preferably set such that the pH of the chemicalsolution falls into the above range.

In the present specification, the pH of the chemical solution is a valuemeasured at room temperature (25° C.) by using F-51 (trade name)manufactured by Horiba, Ltd.

[Method for Manufacturing Chemical Solution]

The chemical solution described above can be manufactured by a knownmethod. Particularly, as an embodiment of the method for manufacturing achemical solution, in view of making it possible to efficientlymanufacture the chemical solution, for example, an embodiment issuitable in which the method has a step A of performing an ion exchangemethod on a substance to be purified including one or more kinds ofperiodic acids selected from the group consisting of a periodic acid anda salt thereof, one or more kinds of first metal components selectedfrom the group consisting of Ti and Zr, and water.

As described above, in some cases, the first metal component is mixedinto the periodic acids in the process of manufacturing the periodicacids. In these cases, the content of the first metal component can beadjusted to prepare the chemical solution. The inventors of the presentinvention have found that in a case where the content of the first metalcomponent is reduced especially by an ion exchange method, it is easy toseparate the first metal component from the periodic acids.

Hereinafter, the procedure of the step A will be specifically described.

<Substance to be Purified>

Hereinafter, each of the components included in the substance to bepurified will be specifically described.

(Periodic Acids)

The substance to be purified includes one or more kinds of periodicacids selected from the group consisting of a periodic acid and a saltthereof. The definition of periodic acids is as described above.

The content of the periodic acids in the substance to be purified is notparticularly limited. However, the content of the periodic acids withrespect to the total mass of the substance to be purified is preferably0.0001% to 50% by mass, more preferably 1% to 45% by mass, and even morepreferably 4% to 40% by mass.

(First Metal Component)

The substance to be purified includes one or more kinds of first metalcomponents selected from the group consisting of Ti and Zr. Thedefinition of the first metal component is as described above.

The content of the first metal component in the substance to be purifiedis not particularly limited. In a case where the substance to bepurified includes one kind of first metal component, in many cases, thecontent of the one kind of first metal component is greater than 100 ppmby mass with respect to the total mass of the periodic acids. The upperlimit thereof is not particularly limited, but is equal to or smallerthan 1% by mass in many cases.

In a case where the substance to be purified includes two kinds of firstmetal components, in many cases, the content of both the two kinds offirst metal components is greater than 100 ppm by mass with respect tothe total mass of the periodic acids. The upper limit thereof is notparticularly limited, but is equal to or smaller than 1% by mass in manycases.

As described above, the first metal component may be separately added tothe substance to be purified so as to prepare the substance to bepurified.

(Water)

The substance to be purified includes water. The definition of water isas described above.

In view of excellent treatment efficiency, the concentration of water inthe substance to be purified is preferably equal to or higher than 40%by mass and less than 100% by mass, preferably 50% to 99% by mass, andmore preferably 60% to 95% by mass.

The substance to be purified may further include <Optional components>which may be included in the chemical solution, in addition to thecomponents described above. Particularly, it is preferable to add a pHadjuster to the substance to be purified, because then the treatmentefficiency can be improved. The pH of the substance to be purified ispreferably 3.0 to 10.0, and more preferably 4.0 to 9.0.

In the present specification, the pH of the substance to be purified ismeasured based on the method for measuring the pH of the chemicalsolution.

<Procedure of Step A>

In the step A, the substance to be purified described above is subjectedto an ion exchange method.

The ion exchange method is not particularly limited as long as theamount of the first metal component in the substance to be purified canbe adjusted (reduced) by the method. In view of more easilymanufacturing the chemical solution, it is preferable that the ionexchange method includes one or more kinds of methods among thefollowing methods A1 to A3. The ion exchange method preferably includestwo or more kinds of methods among the methods A1 to A3, and morepreferably includes all of the methods A1 to A3. In a case where the ionexchange method includes all of the methods A1 to A3, the methods may beperformed in any order without particular limitation, but it ispreferable to perform the methods A1 to A3 in this order.

Method A1: a method of passing the substance to be purified through afirst filled portion filled with a mixed resin including a cationexchange resin and an anion exchange resin.

Method A2: a method of passing the substance to be purified through atleast one kind of filled portion among a second filled portion filledwith a cation exchange resin, a third filled portion filled with ananion exchange resin, and a fourth filled portion filled with achelating resin.

Method A3: a method of passing the substance to be purified through amembranous ion exchanger.

The procedure of the methods A1 to A3 will be specifically describedlater. In a case where the ion exchange resins (the cation exchangeresin and the anion exchange resin), the chelating resin, and themembranous ion exchanger used in the methods are in forms other than H⁺or OH⁻, it is preferable to use the resins and the ion exchanger afterreproducing these in the form of H⁺ or OH⁻.

The space velocity (SV) of the substance to be purified in each of themethods is preferably 0.01 to 20.0 (1/h), and more preferably 0.1 to10.0 (1/h).

The treatment temperature in each of the methods is preferably 0° C. to60° C., and more preferably 10° C. to 50° C.

The ion exchange resins and the chelating resin are in the form of, forexample, particles, fibers, and porous monoliths. It is preferable thatthe ion exchange resins and the chelating resin are in the form ofparticles or fibers.

The average particle size of the ion exchange resins and the chelatingresin in the form of particles is preferably 10 μm to 2,000 μm, and morepreferably 100 μm to 1,000 μm.

Regarding the particle size distribution of the ion exchange resins andthe chelating resin in the form of particles, it is preferable that theabundance ratio of resin particles having a size in a range of averageparticle size±200 μm is equal to or higher than 90%.

The average particle size and the particle size distribution may bemeasured, for example, using a particle size distribution analyzer(Microtrac HRA3920, manufactured by NIKKISO CO., LTD.) and using wateras a dispersion medium.

(Method A1)

The method A1 is a method of passing the substance to be purifiedthrough a first filled portion filled with a mixed resin including acation exchange resin and an anion exchange resin.

As the cation exchange resin, known cation exchange resins can be used.The cation exchange resin may be a gel type or a macroreticular (MR)type resin. Among these, the gel-type cation exchange resin ispreferable.

Specific examples of the cation exchange resin include a sulfonicacid-type cation exchange resin and a carboxylic acid-type cationexchange resin.

Examples of the cation exchange resin include AMBERLITE IR-124,AMBERLITE IR-120B, AMBERLITE IR-200CT, ORLITE DS-1, and ORLITE DS-4(manufactured by ORGANO CORPORATION), DUOLITE C20J, DUOLITE C20LF,DUOLITE C255LFH, and DUOLITE C-433LF (manufactured by Sumika ChemtexCo., Ltd.), C100, C150, and C100×16MBH (manufactured by Purolite),DIAION SK-110, DIAION SK1B, DIAION SK1BH, DIAION PK216, and DIAION PK228(manufactured by Mitsubishi Chemical Corporation.), and the like.

As the anion exchange resin, known anion exchange resins can be used.The anion exchange resin may be a gel type or an MR type. Among these,it is preferable to use the gel-type anion exchange resin.

Specific examples of the cation exchange resin include quaternaryammonium salt-type anion exchange resins.

Examples of the anion exchange resin include AMBERLITE IRA-400J,AMBERLITE IRA-410J, AMBERLITE IRA-900J, AMBERLITE IRA67, ORLITE DS-2,ORLITE DS-5, and ORLITE DS-6 (manufactured by ORGANO CORPORATION),DUOLIGHT A113LF, DUOLIGHT A116, and DUOLIGHT A-375LF (manufactured bySumika Chemtex Co., Ltd.), A400 and A500 (manufactured by Purolite),DIAION SA12A, DIAION SA10AO, DIAION SA10AOH, and DIAION SA20A, andDIAION WA10 (manufactured by Mitsubishi Chemical Corporation.), and thelike.

Examples of commercial products marketed in the form of a premix of astrongly acidic cation exchange resin and a strongly alkaline anionexchange resin include DUOLITE MB5113, DUOLITE UP6000, and DUOLITEUP7000 (manufactured by Sumika Chemtex Co., Ltd.), AMBERLITE EG-4A-HG,AMBERLITE MB-1, AMBERLITE MB-2, AMBERJET ESP-2, AMBERJET ESP-1, ORLITEDS-3, ORLITE DS-7, and ORLITE DS-10 (manufactured by ORGANOCORPORATION), DIAION SMNUP, DIAION SMNUPB, DIAION SMT100L, and DIAIONSMT200L (all manufactured by Mitsubishi Chemical Corporation.), and thelike.

In a case where a mixed resin including a cation exchange resin and ananion exchange resin is prepared, the mixing ratio of the resinsrepresented by a volume ratio of cation exchange resin/anion exchangeresin is preferably ¼ to 4/1, and more preferably ⅓ to 3/1.

As a combination of the cation exchange resin and the anion exchangeresin, for example, a combination of a gel-type sulfonic acid cationexchange resin and a gel-type quaternary ammonium salt anion exchangeresin is suitable.

Generally, the first filled portion includes a container and theaforementioned mixed resin including a cation exchange resin and ananion exchange resin that fills up the container.

Examples of the container include a column, a cartridge, a filledcolumn, and the like. However, containers other than those exemplifiedabove may also be used, as long as the substance to be purified can passthrough the containers filled with the mixed resin.

In the method A1, the substance to be purified may be passed through atleast one first filled portion. Particularly, in view of more easilymanufacturing the chemical solution, the substance to be purified may bepassed through two or more first filled portions.

(Method A2)

The method A2 is a method of passing the substance to be purifiedthrough at least one kind of filled portion (preferably two or morekinds of filled portions) among a second filled portion filled with acation exchange resin, a third filled portion filled with an anionexchange resin, and a fourth filled portion filled with a chelatingresin.

Examples of the cation exchange resin and the anion exchange resin thatcan be used in the method A2 include the cation exchange resins and theanion exchange resins exemplified in the description of the method A1.

Generally, the second filled portion includes a container and theaforementioned cation exchange resin that fills up the container.

Generally, the third filled portion includes a container and theaforementioned anion exchange resin that fills up the container.

Generally, the fourth filled portion includes a container and achelating resin filling up the container that will be described below.

The chelating resin generally refers to a resin having a coordinatinggroup capable of forming a chelate bond with a metal ion.

For example, the chelating resin is a resin obtained by introducing achelate forming group into a styrene-divinylbenzene copolymer or thelike. The material of the chelating resin may be a gel type or an MRtype. In view of treatment efficiency, the chelating resin is preferablyin the form of particles or fibers.

Examples of the chelating resin include various chelating resinsincluding an aminophosphonic acid type such as an iminodiacetic acidtype, an iminopropionic acid type, and an aminomethylphosphonic acidtype, a glucamine type such as a polyamine type and a N-methylglucaminetype, an aminocarboxylic acid type, a dithiocarbamic acid type, a thioltype, an amidoxime type, and a pyridine type.

Specific examples thereof include an iminodiacetate type chelating resinsuch as MC700 manufactured by Sumika Chemtex Co., Ltd., animinopropionic acid type chelating resin such as EPOLAS MX-8manufactured by MIYOSHI OIL & FAT CO., LTD., an aminomethylphosphonicacid-type chelating resin such as MC960 manufactured by Sumika ChemtexCo., Ltd., a polyamine-type chelating resin such as 5985 manufactured byPurolite and DIAION CR-20 manufactured by Mitsubishi ChemicalCorporation., and a N-methylglucamine type chelating resin such asAMBERLITE IRA-743 manufactured by ORGANO CORPORATION.

The definitions of the containers in the second filled portion, thethird filled portion, and the fourth filled portion are as describedabove.

In the method A2, the substance to be purified is passed through atleast one kind of filled portion among the second filled portion, thethird filled portion, and the fourth filled portion. It is particularlypreferable that the substance to be purified is passed through two ormore kinds of filled portions among the second filled portion, the thirdfilled portion, and the fourth filled portion.

In the method A2, it is preferable that the substance to be purified ispasses through at least the second filled portion.

Furthermore, in the method A2, in a case where the substance to bepurified is passed through the fourth filled portion, even though thenumber of times that the substance to be purified is passed through thefilled portions is small, the substance can be efficiently purified.

In a case where the substance to be purified is passed through two ormore kinds of filled portions in the method A2, the substance to bepurified may be passed through two or more kinds of filled portions inany order among the second filled portion, the third filled portion, andthe fourth filled portion.

In the method A2, the substance to be purified may be passed through atleast one second filled portion (preferably two or more second filledportions), at least one third filled portion (preferably two or morethird filled portions), and/or at least one fourth filled portion.

For example, in view of more easily manufacturing the chemical solution,the substance to be purified may be passed through one or more(preferably two or more) second filled portions and one or more(preferably two or more) third filled portions.

In this case, there is no limitation on the order in which the substanceto be purified is passed through the filled portions. For example, thesubstance to be purified may be alternately passed through the secondfilled portion and the third filled portion. Alternatively, thesubstance to be purified may be continuously passed through one of aplurality of second filled portions and a plurality of third filledportions, and then continuously passed through the other ones among theplurality of second filled portions or the plurality of third filledportions.

In addition, in view of more easily manufacturing the chemical solution,the substance to be purified may be passed through one or more secondfilled portions and one or more fourth filled portions.

Even in this case, there is no limitation on the order in which thesubstance to be purified is passed through the filled portions.

(Method A3)

The method A3 is a method of passing the substance to be purifiedthrough a membranous ion exchanger.

The membranous ion exchanger is a membrane having an ion exchange group.Examples of the ion exchange group include a cation exchange group (suchas a sulfonic acid group) and/or an anion exchange group (such as anammonium group).

The membranous ion exchanger may be constituted with an ion exchangeresin, or may be constituted with a membranous support and a cationexchange group and/or an anion exchange group introduced into thesupport. The membranous ion exchanger (including the support of themembranous ion exchanger) may be porous or nonporous. The membranous ionexchanger (including the support of the membranous ion exchanger) may beobtained by forming an aggregate of particles and/or fibers into amembrane.

Furthermore, for example, the membranous ion exchanger may be any of anion exchange membrane, ion exchange nonwoven cloth, ion exchange filterpaper, and ion exchange filter cloth.

The membranous ion exchanger may be used, for example, in a manner inwhich the membranous ion exchanger is incorporated into a cartridge as afilter and an aqueous solution is passed through the filter.

It is preferable to use a semiconductor-grade membranous ion exchanger.

Examples of commercial products of the membranous ion exchanger includeMUSTANG (manufactured by Pall Corporation) and a PROTEGO (registeredtrademark) Plus LT Purifier (manufactured by Entegris).

The thickness of the membranous ion exchanger is not particularlylimited, and is preferably, for example, 0.01 to 1 mm.

The flow rate of the aqueous solution is, for example, 1 to 100ml/(min·cm²).

In the method A3, the substance to be purified may be passed through atleast one membranous ion exchanger. Particularly, in view of more easilymanufacturing the chemical solution, the substance to be purified may bepassed through two or more membranous ion exchangers.

In a case where two or more membranous ion exchangers are used, at leastone membranous ion exchanger having a cation exchange group and at leastone ion exchanger having an anion exchange group may be used.

In view of manufacturing efficiency of the chemical solution, it ispreferable that the ion exchange method is performed until the contentof the first metal component included in the substance to be purifiedsatisfies the requirement on the content (or the condition of thepreferred content) of the first metal component included in the chemicalsolution.

Specifically, the content of the first metal component in the substanceto be purified having been subjected to the ion exchange method ispreferably, for example, 1 ppt by mass to 100 ppm by mass with respectto the total mass of the periodic acids.

Furthermore, in view of efficiently obtaining the chemical solutionhaving higher etching performance, the content is preferably equal to orgreater than 1 ppb by mass. Likewise, in view of efficiently obtainingthe chemical solution having higher defect inhibition performance, thecontent is preferably equal to or smaller than 100 ppb by mass, morepreferably equal to or smaller than 10 ppb by mass, and even morepreferably equal to or smaller than 5 ppb by mass.

<Step B>

In view of reducing the number of particles in the obtained chemicalsolution, it is preferable that the method for manufacturing a chemicalsolution according to the embodiment of the present invention has a stepB of filtering the substance to be purified having undergone the step Aby using a filter after the step A.

The type of the filter is not particularly limited. Examples thereofinclude filters made of a fluororesin such as polytetrafluoroethylene(PTFE), a polyamide-based resin such as nylon, a polyolefin resin(including high-density polyolefin and ultra-high molecular weightpolyolefin) such as polyethylene and polypropylene (PP), and the like.Among these materials, polyethylene (including high-density polyethylene(HDPE)), polypropylene (including high-density polypropylene), or nylonis preferable.

The pore size of the filter is preferably 0.001 to 1.0 μm, morepreferably 0.01 to 0.5 μm, and even more preferably 0.02 to 0.1 μm. In acase where the pore size is within the above range, it is possible toinhibit the clogging of the filter and to control the number of minuteforeign substances such as impurities and aggregates included in thesubstance to be purified.

At the time of using the filter, different filters may be combined. Atthis time, filtering carried out using a first filter may be performedonce or performed two or more times. In a case where filtering isperformed two or more times by using different filters in combination,the pore size for the second filtering and the next filtering may be thesame as or larger than the pore size for the first filtering.Furthermore, first filters having different pore sizes within the aboverange may be combined. As the pore size mentioned herein, the nominalvalues form filter manufacturers can be referred to. A commercial filtercan be selected from various filters provided from, for example, PallCorporation Japan, Advantec Toyo Kaisha, Ltd., Nihon Entegris KK (formerMICRONICS JAPAN CO., LTD.), KITZ MICRO FILTER CORPORATION, or the like.

As a second filter, a filter formed of the same material as theaforementioned first filter and the like can be used.

<Step C>

The method for manufacturing a chemical solution according to theembodiment of the present invention may have a step C of mixing thesubstance to be purified with a pH adjuster before the step A. In a casewhere the step C is performed, it is possible to adjust the pH of thesubstance to be purified subjected to the step A and to further increasethe efficiency of the ion exchange method performed in the step A.

Examples of the pH adjuster used in the Step C include the pH adjustersdescribed above.

As a procedure of the step C, for example, a method of mixing thesubstance to be purified with a pH adjuster may be adopted.

The pH of the substance to be purified having undergone the step C isadjusted to an optimal range according to the ion exchange methodperformed in the step A, but is preferably 3.0 to 10.0 and morepreferably 4.0 to 9.0.

Hitherto, the method for manufacturing a chemical solution by using anion exchange method has been described, but the method for manufacturinga chemical solution according to the embodiment of the present inventionis not limited to the above method.

For example, the chemical solution may be manufactured by mixingtogether periodic acids, the first metal component, and water. Forinstance, in a case where the first metal component is Ti ions, anaqueous solution including periodic acids and water may be brought intocontact with Ti metal such that Ti ions are eluted in the aqueoussolution.

<Use>

The chemical solution according to the embodiment of the presentinvention can be used for various purposes. Particularly, the chemicalsolution can be suitably used for treating a substrate having atransition metal-containing substance.

Hereinafter, the use of the chemical solution for removing a transitionmetal-containing substance on a substrate will be specificallydescribed.

<Step D>

As described above, the chemical solution according to the embodiment ofthe present invention is suitably used for removing a transitionmetal-containing substance on a substrate. In other words, the presentinvention also relates to a method for treating a substrate, including astep D of removing a transition metal-containing substance on asubstrate by using the chemical solution.

In the present specification, “on a substrate” includes, for example,all of the front and back, the lateral surfaces, and the inside ofgrooves of a substrate, and the like. The transition metal-containingsubstance on a substrate includes not only a transition metal-containingsubstance which directly contacts the surface of the substrate but alsoa transition metal-containing substance which is on the substratethrough another layer.

Examples of the transition metal included in the transitionmetal-containing substance include a metal M selected from Ru(ruthenium), Ti (titanium), Ta (tantalum), Co (cobalt), Cr (chromium),Hf (hafnium), Os (osmium), and Pt (platinum), Ni (nickel), Mn(manganese), Cu (copper), Zr (zirconium), Mo (molybdenum), La(lanthanum), W (tungsten), and Jr (iridium).

That is, as the transition metal-containing substance, a substanceincluding the metal M is preferable.

Particularly, the transition metal-containing substance is preferably aRu-containing substance. That is, the chemical solution according to theembodiment of the present invention is more preferably used for removingthe Ru-containing substance.

The content of Ru atoms in the Ru-containing substance with respect tothe total mass of the Ru-containing substance is preferably equal to orgreater than 30% by mass, more preferably equal to or greater than 50%by mass, and even more preferably equal to or greater than 90% by mass.

The transition metal-containing substance is also preferably aCu-containing substance. That is, the chemical solution according to theembodiment of the present invention is also preferably used for removingthe Cu-containing substance.

The content of Cu atoms in the Cu-containing substance with respect tothe total mass of the Cu-containing substance is preferably equal to orgreater than 30% by mass, more preferably equal to or greater than 50%by mass, and even more preferably equal to or greater than 90% by mass.

The transition metal-containing substance only needs to be a substanceincluding a transition metal (transition metal atoms), and examplesthereof include a simple transition metal, an alloy including atransition metal, an oxide of a transition metal, a nitride of atransition metal, and an oxynitride of a transition metal. Among these,as the transition metal-containing substance, simple Ru, an alloy of Ru,an oxide of Ru, a nitride of Ru, or an oxynitride of Ru is preferable.As the transition metal-containing substance, simple Cu, an alloy of Cu,an oxide of Cu, a nitride of Cu, or an oxynitride of Cu is preferable.

Furthermore, the transition metal-containing substance may be a mixtureincluding two or more kinds of compounds among the above compounds.

The oxide, nitride, and oxynitride described above may be a compositeoxide, a composite nitride, and a composite oxynitride including atransition metal.

The content of transition metal atoms in the transition metal-containingsubstance with respect to the total mass of the transitionmetal-containing substance is preferably equal to or greater than 30% bymass, more preferably equal to or greater than 50% by mass, and evenmore preferably equal to or greater than 90% by mass. The upper limitthereof is 100% by mass because the transition metal-containingsubstance may be a transition metal.

The object to be treated is a substrate having a transitionmetal-containing substance. That is, the object to be treated includesat least a substrate and a transition metal-containing substance on thesubstrate.

The type of the substrate is not particularly limited, but is preferablya semiconductor substrate.

Examples of the substrate include various substrates such as asemiconductor wafer, a glass substrate for a photomask, a glasssubstrate for liquid crystal display, a glass substrate for plasmadisplay, a substrate for field emission display (FED), a substrate foran optical disk, a substrate for a magnetic disk, and a substrate for amagneto-optical disk.

Examples of materials constituting the semiconductor substrate includesilicon, silicon germanium, a Group III-V compound such as GaAs, and anycombination of these.

The type of the transition metal-containing substance on the substrateis as described above.

The form of the transition metal-containing substance on the substrateis not particularly limited. For example, the transitionmetal-containing substance may be disposed in the form of a film(transition metal-containing film), in the form of wiring (transitionmetal-containing wiring), or in the form of particles. As describedabove, the transition metal is preferably Ru, and the object to betreated preferably has a substrate and a Ru-containing film,Ru-containing wiring, or a particle-like Ru-containing substance whichis disposed on the substrate. As the transition metal, Cu is alsopreferable, and the object to be treated also preferably has a substrateand a Cu-containing film, Cu-containing wiring, or a particle-likeCu-containing substance which is disposed on the substrate.

It is also preferable that two or more kinds of transitionmetal-containing substances are present on the substrate. For example, aRu-containing substance (such as a Ru-containing film, Ru-containingwiring, and/or a particle-like Ru-containing substance) and aCu-containing substance (such as a Cu-containing film, Cu-containingwiring, and/or a particle-like Cu-containing substance) may be presenton the substrate at the same time. In a case where two or more kinds oftransition metal-containing substances are present on the substrate atthe same time, the two or more kinds of transition metal-containingsubstances may be present separately or present in the form of a uniformmixture.

Examples of the substrate, on which the transition metal-containingsubstance is disposed in the form of particles, include a substrateobtained by performing dry etching on a substrate having a transitionmetal-containing film such that particle-like transitionmetal-containing substances are then attached to the substrate asresidues as will be described later, and a substrate obtained byperforming CMP on the transition metal-containing film such thatparticle-like transition metal-containing substances are then attachedto the substrate as residues as will be described later.

The thickness of the transition metal-containing film is notparticularly limited, and may be appropriately selected according to theuse. For example, the thickness is preferably equal to or smaller than50 nm, more preferably equal to or smaller than 20 nm, and even morepreferably equal to or smaller than 10 nm.

The transition metal-containing film may be disposed only on one of themain surfaces of the substrate, or may be disposed on both the mainsurfaces of the substrate. Furthermore, the transition metal-containingfilm may be disposed on the entire main surface of the substrate, or maybe disposed on a portion of the main surface of the substrate.

The substrate may have various layers and/or structures as desired inaddition to the transition metal-containing substance. For example, thesubstrate may have metal wiring, a gate electrode, a source electrode, adrain electrode, an insulating layer, a ferromagnetic layer, and/or anon-magnetic layer, and the like.

The substrate may have the structure of an exposed integrated circuit,for example, an interconnection mechanism such as metal wiring and adielectric material. Examples of metals and alloys used for theinterconnect mechanism include aluminum, a copper-aluminum alloy,copper, titanium, tantalum, cobalt, silicon, titanium nitride, tantalumnitride, and tungsten. The substrate may have a layer of silicon oxide,silicon nitride, silicon carbide, and/or carbon-doped silicon oxide.

The size, thickness, shape, layer structure, and the like of thesubstrate are not particularly limited, and can be appropriatelyselected as desired.

As described above, the object to be treated used in the treatmentmethod according to the embodiment of the present invention has atransition metal-containing substance on a substrate.

The method for manufacturing the substrate having the transitionmetal-containing substance is not particularly limited. For example, atransition metal-containing film can be formed on a substrate by asputtering method, a chemical vapor deposition (CVD) method, a molecularbeam epitaxy (MBE) method, or the like. In a case where the transitionmetal-containing film is formed by a sputtering method, a CVD method, orthe like, sometimes the transition metal-containing substance is alsoattached to the back surface of the substrate having the transitionmetal-containing film (the surface opposite to the side of thetransition metal-containing film).

Furthermore, transition metal-containing wiring may be formed on asubstrate by performing the aforementioned method through apredetermined mask.

In addition, after the transition metal-containing film or thetransition metal-containing wiring is formed on a substrate, thesubstrate may be further subjected to a different process or treatmentand then used as the object to be treated by the treatment method of thepresent invention.

For example, by performing dry etching on a substrate having atransition metal-containing film or transition metal-containing wiring,a substrate having dry etching residues including a transition metal maybe manufactured. Furthermore, by performing CMP on a substrate having atransition metal-containing film or transition metal-containing wiring,a substrate having a transition metal-containing substance may bemanufactured.

Examples of the specific method of the step D include a method ofbringing the substrate having a transition metal-containing substance,which is an object to be treated, into contact with the chemicalsolution.

The method of bringing the substrate into contact with the chemicalsolution is not particularly limited, and examples thereof include amethod of immersing the object to be treated in the chemical solutionput in a tank, a method of spraying the chemical solution onto thesubstrate, a method of causing the chemical solution to flow on thesubstrate, and any combination of these. Among these, the method ofimmersing the substrate having a transition metal-containing substance,which is an object to be treated, in the chemical solution ispreferable.

The treatment time of the step D can be adjusted according to the methodof bringing the chemical solution into contact with the substrate, thetemperature of the chemical solution, and the like. The treatment time(the contact time between the chemical solution and the object to betreated) is not particularly limited, but is preferably 0.01 to 30minutes, and more preferably 0.1 to 5 minutes.

The temperature of the chemical solution during the treatment is notparticularly limited, but is preferably 20° C. to 75° C., morepreferably 30° C. to 65° C., and even more preferably 40° C. to 65° C.The temperature is still more preferably 50° C. to 65° C.

In the step D, only one kind of transition metal-containing substance ortwo or more kinds of transition metal-containing substances may beremoved from the substrate.

In a case where two or more kinds of transition metal-containingsubstances are removed by the step D, the two or more kinds oftransition metal-containing substances may be removed simultaneously bya single treatment or may be separately treated.

Examples of the combination of two or more kinds of transitionmetal-containing substances include a combination of substancesincluding two or more kinds of metals among the metals M described above(two or more kinds of metal M-containing substances). Among these, acombination including at least a Ru-containing substance and aCu-containing substance is preferable.

Specifically, examples of suitable embodiments of the step D include astep D1 of performing a recess etching treatment on transitionmetal-containing wiring disposed on a substrate by using the chemicalsolution, a step D2 of removing a transition metal-containing film onouter edge portions of a substrate, on which the transitionmetal-containing film is disposed, by using the chemical solution, astep D3 of removing a transition metal-containing substance attached toa back surface of a substrate, on which a transition metal-containingfilm is disposed, by using the chemical solution, a step D4 of removinga transition metal-containing substance on a substrate, which hasundergone dry etching, by using the chemical solution, and a step D5 ofremoving a transition metal-containing substance on a substrate, whichhas undergone a chemical mechanical polishing treatment, by using thechemical solution.

Among these, as the step D, the step D1, the step D2, or the step D3 ispreferable, and the step D2 or the step D3 is more preferable.

Hereinafter, the steps D1 to D3 will be specifically described.

Step D1

Examples of the step D include a step D1 of performing a recess etchingtreatment on transition metal-containing wiring disposed on a substrateby using the chemical solution.

FIG. 1 is a schematic cross-sectional top view showing an example of asubstrate having transition metal-containing wiring (hereinafter,referred to as “wiring substrate” as well) which is an object to betreated by the recess etching treatment in the step D1.

A wiring substrate 10 a shown in FIG. 1 has a substrate not shown in thedrawing, an insulating film 12 (interlayer insulating film 12) having agroove disposed on the substrate, a barrier metal layer 14 disposedalong the inner wall of the groove, and transition metal-containingwiring 16 that fills up the inside of the groove.

The substrate and the transition metal-containing wiring in the wiringsubstrate are as described above.

As the transition metal-containing wiring, Ru-containing wiring (wiringincluding Ru) is preferable. It is preferable that the Ru-containingwiring includes simple Ru, an alloy of Ru, an oxide of Ru, a nitride ofRu, or an oxynitride of Ru.

As the transition metal-containing wiring, Cu-containing wiring (wiringincluding Cu) is also preferable. It is preferable that theCu-containing wiring includes simple Cu, an alloy of Cu, an oxide of Cu,a nitride of Cu, or an oxynitride of Cu.

The material constituting the barrier metal layer in the wiringsubstrate is not particularly limited, and examples thereof include TiNand TaN.

In FIG. 1 , an embodiment is illustrated in which the wiring substratehas a barrier metal layer. However, the wiring substrate may not havethe barrier metal layer.

A liner layer may be disposed between the barrier metal layer 14 and thetransition metal-containing wiring 16, although the liner layer is notshown in FIG. 1 . The material constituting the liner layer is notparticularly limited, and examples thereof include a Ru-containingsubstance and a Cu-containing substance.

The method for manufacturing the wiring substrate is not particularlylimited, and examples thereof include a method including a step offorming an insulating film on a substrate, a step of forming a groove inthe insulating film, a step of forming a barrier metal layer on theinsulating film, a step of forming a transition metal-containing filmthat fills up the groove, and a step of performing a smoothing treatmenton the transition metal-containing film.

The method for manufacturing the wiring substrate may include a step offorming a liner layer on the barrier metal layer between the step offorming a barrier metal layer on the insulating film and the step offorming a transition metal-containing film for filling up the groove.

In the step D1, by performing a recess etching treatment on thetransition metal-containing wiring in the wiring substrate by using theaforementioned chemical solution, a portion of the transitionmetal-containing wiring can be removed, and a recess portion can beformed.

More specifically, in a case where the step D1 is performed, as shown inthe wiring substrate 10 b in FIG. 2 , a portion of the barrier metallayer 14 and the transition metal-containing wiring 16 is removed, and arecess portion 18 is formed.

Examples of the specific method of the step D1 include a method ofbringing the wiring substrate into contact with the chemical solution.

The method of bringing the wiring substrate into contact with thechemical solution is as described above.

The suitable ranges of the contact time between the chemical solutionand the wiring substrate and the temperature of the chemical solutionare as described above.

After the step D1, if necessary, a step Db of treating the substrateobtained by the step D1 by using a predetermined solution (hereinafter,referred to as “specific solution” as well) may be performed.

Particularly, as described above, in a case where the barrier metallayer is disposed on the substrate, the solubility in the chemicalsolution according to the embodiment of the present invention variesbetween the component constituting the transition metal-containingwiring and the component constituting the barrier metal layer dependingon the type of the components. In this case, it is preferable to adjustthe degree of solubility of the transition metal-containing wiring andthe barrier metal layer by using a solution that dissolves better thebarrier metal layer.

In this respect, as the specific solution, a solution is preferablewhich poorly dissolves the transition metal-containing wiring butexcellently dissolves the substance constituting the barrier metallayer.

Examples of the specific solution include a solution selected from thegroup consisting of a mixed solution of hydrofluoric acid and aqueoushydrogen peroxide (FPM), a mixed solution of sulfuric acid and aqueoushydrogen peroxide (SPM), a mixed solution of aqueous ammonia and aqueoushydrogen peroxide (APM), and a mixed solution of hydrochloric acid andaqueous hydrogen peroxide (HPM).

The composition of FPM is, for example, preferably in a range of“hydrofluoric acid:aqueous hydrogen peroxide:water=1:1:1” to“hydrofluoric acid:aqueous hydrogen peroxide:water=1:1:200” (volumeratio).

The composition of SPM is, for example, preferably in a range of“sulfuric acid:aqueous hydrogen peroxide:water=3:1:0” to “sulfuricacid:aqueous hydrogen peroxide:water=1:1:10” (volume ratio).

The composition of APM is, for example, preferably in a range of“aqueous ammonia:aqueous hydrogen peroxide:water=1:1:1” to “aqueousammonia:aqueous hydrogen peroxide:water=1:1:30” (volume ratio).

The composition of HPM is, for example, preferably in a range of“hydrochloric acid:aqueous hydrogen peroxide:water=1:1:1” to“hydrochloric acid:aqueous hydrogen peroxide:water=1:1:30” (volumeratio).

The preferred compositional ratio described above means a compositionalratio determined in a case where the content of hydrofluoric acid is 49%by mass, the content of sulfuric acid is 98% by mass, the content ofaqueous ammonia is 28% by mass, the content of hydrochloric acid is 37%by mass, and the content of aqueous hydrogen peroxide is 31% by mass.

Among these, in view of dissolving ability for the bather metal layer,SPM, APM, or HPM is preferable.

In view of reducing roughness, APM, HPM, or FPM is preferable, and APMis more preferable.

In view of achieving excellent balance between performances, APM or HPMis preferable.

In the step Db, as the method of treating the substrate obtained by thestep D1 by using the specific solution, a method of bringing thesubstrate obtained by the step D1 into contact with the specificsolution is preferable.

The method of bringing the substrate obtained by the step D1 intocontact with the specific solution is not particularly limited, andexamples thereof include the same method as the method of bringing thesubstrate into contact with the chemical solution.

The contact time between the specific solution and the substrateobtained by the step D1 is, for example, preferably 0.25 to 10 minutes,and more preferably 0.5 to 5 minutes.

In the present treatment method, the step D1 and the step Db may beperformed alternately.

In a case where the steps are performed alternately, it is preferablethat each of the step D1 and the step Db is performed 1 to 10 times.

The step D1 is also preferably a step D1X of simultaneously removing twoor more transition metal-containing substances (for example, two or morekinds of metal M-containing substances and preferably a combination of aRu-containing substance and a Cu-containing substance).

The step D1X is performed, for example, on a wiring substrate whichcontains at least transition metal-containing wiring and a liner layer,in which the transition metal-containing wiring and the liner layer aredifferent transition metal-containing substances.

In this case, for example, the wiring substrate is preferably asubstrate in which the transition metal-containing wiring isCu-containing wiring and the liner layer is a Ru-containing substance ora substrate in which the transition metal-containing wiring isRu-containing wiring and the liner layer is a Cu-containing substance,and more preferably a substrate in which the transition metal-containingwiring is Cu-containing wiring and the liner layer is a Ru-containingsubstance.

In a case where the step D1X is performed (preferably in a case where aCu-containing substance is included in two or more kinds of transitionmetal-containing substances and more preferably in a case where aRu-containing substance and a Cu-containing substance are included intwo or more kinds of transition metal-containing substances), in view offurther improving the balance between the etching rate and the surfacecondition (smoothness and the like) of the portion to be treated, the pHof the chemical solution is preferably 3.0 to 10.0, more preferably 7.5to 10.0, and even more preferably 8.0 to 10.0.

It is considered that in a case where the pH of the chemical solution is7.5 to 10.0 (preferably 8.0 to 10.0), the chemical solution may etch thetransition metal-containing substance while forming a layer on thesurface of the treated transition metal-containing substance(particularly the Cu-containing substance). Presumably, as a result, thesurface properties of the transition metal-containing wiring and thelike may be excellent after the treatment (for example, the surface isnot oxidized and has excellent smoothness).

Even in a case where the step D1 is the step D1X, the step Db may beperformed after the step D1X or alternately with the step D1X.

Step D2

Examples of the step D include a step D2 of removing a transitionmetal-containing film at the outer edge portion of a substrate, on whichthe transition metal-containing film is disposed, by using the chemicalsolution.

FIG. 3 is a schematic view (top view) showing an example of a substrate,on which a transition metal-containing film is disposed, as an object tobe treated by the step D2.

An object 20 to be treated by the step D2 shown in FIG. 3 is a laminatehaving a substrate 22 and a transition metal-containing film 24 disposedon one main surface (entire region surrounded by the solid line) of thesubstrate 22. As will be described later, in step D2, the transitionmetal-containing film 24 positioned at an outer edge portion 26 (theregion outside the broken line) of the object 20 to be treated isremoved.

The substrate and the transition metal-containing film in the object tobe treated are as described above.

As the transition metal-containing film, a Ru-containing film (filmincluding Ru) is preferable. It is preferable that the Ru-containingfilm includes simple Ru, an alloy of Ru, an oxide of Ru, a nitride ofRu, or an oxynitride of Ru.

The specific method of the step D2 is not particularly limited, andexamples thereof include a method of supplying the chemical solutionfrom a nozzle such that the chemical solution contacts only thetransition metal-containing film at the outer edge portion of thesubstrate.

At the time of performing the treatment of the step D2, it is possibleto preferably use the substrate treatment device and the substratetreatment method described in JP-2010-267690A, JP2008-080288A,JP2006-100368A, and JP2002-299305A.

The method of bringing the object to be treated into contact with thechemical solution is as described above.

The suitable ranges of the contact time between the chemical solutionand the object to be treated and the temperature of the chemicalsolution are as described above.

Step D3

Examples of the step D include a step D3 of removing a transitionmetal-containing substance attached to the back surface of a substrate,on which a transition metal-containing film is disposed, by using thechemical solution.

Examples of the object to be treated by the step D3 include the objectto be treated used in the step D2. At the time of forming the object tobe treated, which is constituted with a substrate and a transitionmetal-containing film disposed on one main surface of the substrate,used in the step D2, the transition metal-containing film is formed bysputtering, CVD, or the like. At this time, sometimes a transitionmetal-containing substance is attached to a surface (back surface) ofthe substrate that is opposite to the transition metal-containing film.The step D3 is performed to remove such a transition metal-containingsubstance in the object to be treated.

The specific method of the step D3 is not particularly limited, andexamples thereof include a method of spraying the chemical solution suchthat the chemical solution contacts only the back surface of thesubstrate.

The method of bringing the object to be treated into contact with thechemical solution is as described above.

The suitable ranges of the contact time between the chemical solutionand the object to be treated and the temperature of the chemicalsolution are as described above.

It is also preferable to perform a rinsing treatment after bringing thechemical solution into contact with the object to be treated.

In a case where the object to be treated is brought into contact withthe chemical solution according to the embodiment of the presentinvention, sometimes an iodine compound derived from the chemicalsolution according to the embodiment of the present invention isattached to the surface of the object to be treated as residual iodine(I residue). Such residual iodine (I residue) may negatively affect thesubsequent processes and/or end products. By performing the rinsingtreatment, it is possible to remove the residual iodine (I residue) fromthe surface of the object to be treated.

Furthermore, by the rinsing treatment, it is also possible to remove theresidues of the removed transition metal-containing substance that occuron the surface of the object to be treated by the step D1.

The rinsing treatment is preferably performed by a method of bringing arinsing solution into contact with the object to be treated.

The method of bringing the substrate into contact with the rinsingsolution is performed, for example, by immersing the object to betreated in the rinsing solution put in a tank, spraying the rinsingsolution to the surface of the object to be treated, causing the rinsingsolution to flow on the surface of the object to be treated, or anycombination of these.

As the rinsing solution, for example, hydrofluoric acid, hydrochloricacid, aqueous hydrogen peroxide, a mixed solution of hydrofluoric acidand aqueous hydrogen peroxide (FPM), a mixed solution of sulfuric acidand aqueous hydrogen peroxide (SPM), a mixed solution of aqueous ammoniaand aqueous hydrogen peroxide (APM), a mixed solution of hydrochloricacid and aqueous hydrogen peroxide (HPM), aqueous carbon dioxide,aqueous ozone, aqueous hydrogen, an aqueous citric acid solution,sulfuric acid, aqueous ammonia, isopropyl alcohol, an aqueoushypochlorous acid solution, aqua regia, ultrapure water, nitric acid,perchloric acid, an aqueous oxalic acid solution, acetic acid (includingan aqueous acetic acid solution), or an aqueous orthoperiodic acidsolution is preferable.

As the rinsing solution, an acidic rinsing solution is preferable,because this solution can efficiently remove the residues of the removedtransition metal-containing substance that occur on the surface of theobject to be treated by the step D1 (particularly the step D1X), andimproves the surface properties of the substrate after the treatment(particularly, the surface properties of the transition metal-containingwiring and the like after the treatment).

Examples of the acidic rinsing solution include an aqueous citric acidsolution (preferably a 0.01% to 10% by mass aqueous citric acidsolution), hydrofluoric acid (preferably 0.001% to 1% by masshydrofluoric acid), hydrochloric acid (preferably 0.001% to 10% by masshydrochloric acid), aqueous hydrogen peroxide (preferably 0.5% to 31% bymass aqueous hydrogen peroxide, and more preferably 3% to 15% by massaqueous hydrogen peroxide), a mixed solution of hydrofluoric acid andaqueous hydrogen peroxide (FPM), a mixed solution of sulfuric acid andaqueous hydrogen peroxide (SPM), a mixed solution of hydrochloric acidand aqueous hydrogen peroxide (HPM), carbon dioxide (preferably 10 to 60ppm by mass carbon dioxide), aqueous ozone (preferably 10 to 60 ppm bymass aqueous ozone), aqueous hydrogen (preferably 10 to 20 ppm by massaqueous hydrogen), sulfuric acid (preferably 1% to 10% by mass aqueoussulfuric acid solution), and an aqueous hypochlorous acid solution(preferably a 1% to 10% by mass aqueous hypochlorous acid solution),aqua regia (preferably aqua regia obtained by mixing together 37% bymass hydrochloric acid:60% by mass nitric acid at a volume ratio of2.6:1.4 to 3.4:0.6), nitric acid (preferably 0.001% to 1% by mass nitricacid), perchloric acid (preferably 0.001% to 1% by mass perchloricacid), an aqueous oxalic acid solution (preferably a 0.01% to 10% bymass aqueous oxalic acid solution), acetic acid (preferably a 0.01% to10% by mass aqueous acetic acid solution or an undiluted acetic acidsolution), and an aqueous periodic acid solution (preferably a 0.5% to10% by mass aqueous periodic acid solution). As the periodic acid, forexample, orthoperiodic acid and metaperiodic acid are preferable. Amongthese, an aqueous citric acid solution is more preferable.

Preferred conditions for FPM, SPM, APM, and HPM are, for example, thesame as the preferred conditions for FPM, SPM, APM, and HPM used as thespecific solution described above.

The hydrofluoric acid, nitric acid, perchloric acid, and hydrochloricacid mean aqueous solutions obtained by dissolving HF, HNO₃, HClO₄, andHCl in water respectively.

The aqueous ozone, aqueous carbon dioxide, and aqueous hydrogen meanaqueous solutions obtained by dissolving O₃, CO₂, and H₂ in waterrespectively.

As long as the purpose of the rinsing step is not impaired, theserinsing solutions may be used by being mixed together.

The treatment time (contact time between the rinsing solution and theobject to be treated) of the rinsing treatment is not particularlylimited, but is 5 seconds to 5 minutes for example.

The temperature of the rinsing solution during the treatment is notparticularly limited. Generally, for example, the temperature of therinsing solution is preferably 16° C. to 60° C., and more preferably 18°C. to 40° C. In a case where SPM is used as the rinsing solution, thetemperature is preferably 90° C. to 250° C.

Furthermore, the rinsing solution may include an organic solvent.

EXAMPLES

Hereinafter, the present invention will be more specifically describedbased on examples. The materials, the amounts and ratios of thematerials used, the details of treatments, the procedures of treatments,and the like shown in the following examples can be appropriatelychanged as long as the gist of the present invention is maintained.Therefore, the scope of the present invention is not restricted by thefollowing examples.

Example X

An aqueous solution (substance to be purified) including a periodic acidand the like was treated by an ion exchange method which will bedescribed later.

The raw materials used for preparing the aqueous solution are asfollows.

-   -   Water: ultrapure water (ultrapure water manufactured by an        ultrapure water manufacturing device “PURELAB Ultra”        (manufactured by ORGANO CORPORATION))    -   Orthoperiodic acid: reagent A (orthoperiodic acid including Ti        and Zr)

(PH adjuster)

-   -   TMAH: Tetramethylammonium hydroxide    -   TEAH: Tetraethylammonium hydroxide    -   TBAH: Tetrabutylammonium hydroxide    -   DBU: diazabicycloundecene

All the pH adjusters used were classified as a semiconductor grade.

<Ion Exchange Resin or Membranous Ion Exchanger>

The ion exchange resins and membranous ion exchangers used in themethods A1 to A3, which will be described later, are as follows.

-   -   (Mixed resin (used in method A1))    -   DS-3: ORLITE DS-3 (manufactured by ORGANO CORPORATION)    -   DS-7: ORLITE DS-7 (manufactured by ORGANO CORPORATION)    -   DS-10: ORLITE DS-10 (manufactured by ORGANO CORPORATION)    -   SMNUPB: DIAION SMNUPB (manufactured by Mitsubishi Chemical        Corporation.)    -   SMT100L: DIAION SMT100L (manufactured by Mitsubishi Chemical        Corporation.)    -   SMT200L: DIAION SMT200L (manufactured by Mitsubishi Chemical        Corporation.)

(Cation exchange resin, anion exchange resin, and chelating resin (usedin method A2))

-   -   DS-1: ORLITE DS-1 (manufactured by ORGANO CORPORATION)    -   DS-4: ORLITE DS-4 (manufactured by ORGANO CORPORATION)    -   200CT: AMBERLITE 200CT (manufactured by ORGANO CORPORATION        (semiconductor grade))    -   SK1BH: DIAION SK1BH (manufactured by Mitsubishi Chemical        Corporation.)    -   PK216: DIAION PK216 (manufactured by Mitsubishi Chemical        Corporation.)    -   PK228: DIAION PK228 (manufactured by Mitsubishi Chemical        Corporation.)    -   RCP160M: DIAION RCP160M (manufactured by Mitsubishi Chemical        Corporation.)    -   C100: PUROLITE C100 (manufactured by Purolite)    -   C150: PUROLITE C150 (manufactured by Purolite)    -   C100x16MBH: PUROLITE C100x16MBH (manufactured by Purolite)    -   C255LFH: DUOLITE C255LFH (manufactured by Sumika Chemtex Co.,        Ltd.)    -   C20J: DUOLIGHT C20J (manufactured by Sumika Chemtex Co., Ltd.)    -   DS-2: ORLITE DS-2 (manufactured by ORGANO CORPORATION)    -   DS-5: ORLITE DS-5 (manufactured by ORGANO CORPORATION)    -   DS-6: ORLITE DS-6 (manufactured by ORGANO CORPORATION)    -   IRA900J: AMBERLITE IRA900J (manufactured by ORGANO CORPORATION)        (non-semiconductor grade))    -   SA10AOH: DIAION SA10AOH (manufactured by Mitsubishi Chemical        Corporation.)    -   A500: PUROLITE A500 (manufactured by Purolite)    -   A113LF: DUOLIGHT A113LF (manufactured by Sumika Chemtex Co.,        Ltd.)    -   A116: DUOLIGHT A116 (manufactured by Sumika Chemtex Co., Ltd.)    -   S985: PUROLITE S985 (manufactured by Purolite)    -   MC700: SUMICHELATE MC700 (manufactured by Sumika Chemtex Co.,        Ltd.)    -   MC960: SUMICHELATE MC960 (manufactured by Sumika Chemtex Co.,        Ltd.)

(Membranous Ion Exchanger (Used in Method A3))

-   -   Mustang: MUSTANG Q (manufactured by Pall Corporation)    -   Purifier: PROTEGO (R) Plus LT Purifier (manufactured by        Entegris.)

<Treatment method>

(Preparation of Aqueous Solution (Substance to be Purified)) Theaforementioned orthoperiodic acid and a pH adjuster, which was used ifnecessary, were dissolved in water, thereby preparing aqueous solutionshaving the formulation described in the following Table 1.

(Ion Exchange Method)

By using the ion exchange resin or the membranous ion exchangerdescribed in Table 1, one or more ion exchange methods selected from thegroup consisting of the method A1, the method A2, and the method A3,which will be described later, were performed, thereby treating the eachof the aqueous solutions (500 g).

In a case where two or more steps were performed, the same aqueoussolution was sequentially treated by the method A1, the method A2, andthe method A3 in this order. In the following Table 1, a blank meansthat the aqueous solution was not treated by the corresponding method.

Method A1

A vertically set column (inner volume: 300 ml) was filled with the firstmixed resin (150 ml) shown in the field of “1” of the field of “Mixedresin” in the following Table 1. An aqueous solution was passed throughthis column at a space velocity (SV) of 1.4 (1/h).

In the examples described in the field of “2” of the field of “Mixedresin” and the field of “3” of the field of “Mixed resin” in Table 1,each column was filled with the mixed resin (150 ml) described in eachfield, and the aqueous solution was passed through the column. In a casewhere the aqueous solution was passed through a plurality of columns,the aqueous solution was passed through the columns in the fields of“1”, “2”, and “3” in this order.

In a series of operations, all of the mixed resin, the aqueous solution,and the like were kept at a temperature of 10° C.

Method A2

A vertically set column (inner volume: 300 ml) was filled with a firstcation exchange resin (75 ml) described in the field of “1” of the fieldof “Acidic cation exchange resin” shown in the following table. This iscalled first cation exchange column.

Likewise, a vertically set column (inner volume: 300 ml) was filled witha first anion exchange resin (75 ml) described in the field of “1” ofthe field of “Basic anion exchange resin” shown in the following table.This is called first anion exchange column.

Similarly, a vertically set column (inner volume: 300 ml) was filledwith a first chelating resin (75 ml) described in the field of “1” ofthe field of “Chelating resin” shown in the following table. This iscalled first chelating resin column.

The aqueous solution was passed through the first cation exchange columnand then, as desired, through the first anion exchange column or thefirst chelating resin column.

In addition, in a case where a second acidic cation exchange resindescribed in the field of “2” of the field of “Acidic cation exchangeresin” and a second basic anion exchange resin described in the field of“2” of the field of “Basic anion exchange resin”were used, the aqueoussolution was further passed through the second cation exchange column(prepared in the same manner as the first cation exchange column) andthen passed through the second anion exchange column (prepared in thesame manner as the first anion exchange column).

The aqueous solution was passed through the columns at a space velocity(SV) of 1.4 (1/h) all the time. In a series of operations, all of thecation exchange resin, the anion exchange resin, the chelating resin,the aqueous solution, and the like were kept at a temperature of 10° C.

The cation exchange resin and the anion exchange resin, which were informs other than H⁺ or the OH⁻, were used for the test after beingreproduced as resins in the form of H⁺ or the OH⁻.

Method A3

The aqueous solution was passed through the first ion-exchange resinmembrane (0.02 cm²) shown in the field of “1” of the field of “Ionexchange membrane” in the following table at 100 ml/min.

In a case where the second membranous ion exchanger shown in the fieldof “2” of the field of “Ion-exchange membrane”was used, the aqueoussolution having been passed through the first ion-exchange membrane wasalso passed through the second membranous ion exchanger.

In a series of operations, all of the membranous ion exchanger, theaqueous solution, and the like were kept at a temperature of 10° C.

(Step B)

In some examples and comparative examples, the aqueous solution havingbeen subjected to the ion exchange method was further subjected to thestep B of filtering the solution by using a filter. As the filter, ahigh-density polyethylene (HDPE) filter having a pore size of 10 nm wasused.

In Comparative Example A1, a step of filtering the aqueous solution byusing a filter was performed without performing the ion exchange method.

[Evaluation]

The content of Ti and Zr included in the treated aqueous solution ineach of the examples and comparative examples was measured using Agilent8800 triple quadrupole inductively coupled plasma mass spectrometry(ICP-MS, for semiconductor analysis, option #200).

(Measurement Condition)

As a sample introduction system, a quartz torch, a coaxialperfluoroalkoxyalkane (PFA) nebulizer (for self-suction), and a platinuminterface cone were used. The measurement parameters of cool plasmaconditions are as follows.

-   -   Output of Radio Frequency (RF) (W): 600    -   Flow rate of carrier gas (L/min): 0.7    -   Flow rate of makeup gas (L/min): 1    -   Sampling depth (mm): 18

In measuring the content of Ti and Zr, the aqueous solution for whichthe content of Ti and Zr is to be determined was generally adopted as ameasurement target. In a case where the aqueous solution was adopted asa measurement target, and the content of Ti and Zr in the aqueoussolution was less than the detection limit, the aqueous solution as ameasurement target was measured again after being appropriatelyconcentrated, and the value obtained by the measurement was convertedinto the concentration of the aqueous solution not yet beingconcentrated, thereby calculating the content of Ti and Zr.

By using such a method, the content of Ti and Zr with respect to thetotal mass of periodic acids can be determined to 0.1 ppt by mass.

In the present specification, in a case where the content of Ti and/orZr with respect to the total mass of periodic acids is less than 0.1 pptby mass, the aqueous solution (and the periodic acids included in suchan aqueous solution) is regarded as not including Ti and/or Zr.

From the measured content of Ti and Zr included in the treated aqueoussolution, the content of Ti and Zr with respect to the total mass of theperiodic acids in the treated aqueous solution was calculated. Theobtained calculation results were classified based on the followingstandard, and the purification effect of the treatment method in eachtest example was evaluated.

−: The content is less than 1 ppt by mass.

-   -   A: The content is equal to or greater than 1 ppt by mass and        less than 1 ppb by mass.    -   B: The content is equal to or greater than 1 ppb by mass and        less than 10 ppb by mass.    -   C: The content is equal to or greater than 10 ppb by mass and        less than 100 ppb by mass.    -   D: The content is equal to or greater than 100 ppb by mass and        equal to or smaller than 1 ppm by mass.    -   E: The content is greater than 1 ppm by mass and equal to or        smaller than 100 ppm by mass.    -   F: The content is greater than 100 ppm by mass.

Table 1 shows the conditions of each test, and Table 2 shows theoverview and results of each test.

In Table 1, the field of “Step B” shows whether or not the aqueoussolution treated by the ion exchange method was further subjected tofiltration (step B). A means that filtration (step B) was performed, andB means that filtration (step B) was not performed.

In Table 1, the description of “Balance” in the field of “Content” for“Water” shows that the rest of the components other than water describedin the table is water.

In Table 1, the description of “Adjusted” in the field of “Content” for“pH adjuster” shows the aqueous solution includes a pH adjuster in suchan amount that the aqueous solution has a predetermined pH.

The pH of the aqueous solutions in Examples X115 to X124 was 1.8, 4.0,4.0, 4.0, 4.0, 4.0, 4.0, 4.0, 4.0, and 4.0 respectively.

In Table 2, the field of “Number of kinds of ion exchange methods” showsthe number of kinds of performed methods among the methods A1, A2, andA3.

In Table 2, the field of “Number of kinds of mixed resins” shows thenumber of mixed resins used in a case where the method A1 was applied.

In Table 2, the field of “Number of kinds of non-mixed resins” shows thenumber of cation exchange resins, the number of anion exchange resins,and the number of chelating resins used in a case where the method A2was applied.

In Table 2, the field of “Number of kinds of membranous ion exchangers”shows the number of kinds of membranous ion exchangers used in a casewhere the method A3 was applied.

In Table 2, the field of “Step B” has the same definition as the fieldof “Step B” in Table 1.

TABLE 1 Ion exchange method Formulation of aqueous solution Method A2 pHAcidic Method A3 Periodic acids adjuster cation Basic anion MembranousContent Content Method A1 exchange exchange Chelating ion Water (% by (%by Mixed resin resin resin resin exchanger Content Type mass) Type mass)1 2 3 1 2 1 2 1 1 2 Step B Example X1 Balance Orthoperiodic 37 DS-3 Aacid Example X2 Balance Orthoperiodic 37 DS-7 A acid Example X3 BalanceOrthoperiodic 37 DS-10 A acid Example X4 Balance Orthoperiodic 37 SMNUPBA acid Example X5 Balance Orthoperiodic 37 SMT100L A acid Example X6Balance Orthoperiodic 37 SMT200L A acid Example X7 Balance Orthoperiodic37 DS-1 DS-2 A acid Example X8 Balance Orthoperiodic 37 DS-1 DS-5 A acidExample X9 Balance Orthoperiodic 37 DS-1 DS-6 A acid Example X10 BalanceOrthoperiodic 37 DS-4 DS-2 A acid Example X11 Balance Orthoperiodic 37DS-4 DS-5 A acid Example X12 Balance Orthoperiodic 37 DS-4 DS-6 A acidExample X13 Balance Orthoperiodic 37 SK1BH SA10AOH A acid Example X14Balance Orthoperiodic 37 PK216 SA10AOH A acid Example X15 BalanceOrthoperiodic 37 PK228 SA10AOH A acid Example X16 Balance Orthoperiodic37 RCP160M SA10AOH A acid Example X17 Balance Orthoperiodic 37 C100 A500A acid Example X18 Balance Orthoperiodic 37 C150 A500 A acid Example X19Balance Orthoperiodic 37 C100 × A500 A acid 16MBH Example X20 BalanceOrthoperiodic 37 C255LFH A113LF A acid Example X21 Balance Orthoperiodic37 C255LFH A116 A acid Example X22 Balance Orthoperiodic 37 C20J A113LFA acid Example X23 Balance Orthoperiodic 37 C20J A116 A acid

TABLE 2 Formulation of aqueous solution Ion exchange method pH Method A2Periodic acids adjuster Method A1 Acidic Basic Method A3 Water ContentContent Mixed resin cation exchange resin anion exchange resin Chelatingresin Membranous ion exchanger Step Content Type (% by mass) Type (% bymass) 1 2 3 1 2 1 2 1 1 2 B Example X24 Balance Orthoperiodic 37 DS-1 Aacid Example X25 Balance Orthoperiodic 37 DS-4 A acid Example X26Balance Orthoperiodic 37 C100 S985 A acid Example X27 BalanceOrthoperiodic 37 C255LFH MC700 A acid Example X28 Balance Orthoperiodic37 C255LFH MC960 A acid Example X29 Balance Orthoperiodic 37 Mustang Aacid Example X30 Balance Orthoperiodic 37 Purifier A acid Example X31Balance Orthoperiodic 37 DS-3 DS-77 A acid Example X32 BalanceOrthoperiodic 37 DS-3 DS-10 A acid Example X33 Balance Orthoperiodic 37DS-7 DS-10 A acid Example X34 Balance Orthoperiodic 37 DS-7 DS-10 B acidExample X35 Balance Orthoperiodic 37 SMNUPB SMT100L A acid Example X36Balance Orthoperiodic 37 SMNUPB SMT200L A acid Example X37 BalanceOrthoperiodic 37 SMT100L SMT200L A acid Example X38 BalanceOrthoperiodic 37 DS-7 DS-10 SMT100L A acid Example X39 BalanceOrthoperiodic 37 DS-7 DS-10 SMT200L A acid Example X40 BalanceOrthoperiodic 37 DS-7 SMNUPB SMT100L A acid Example X41 BalanceOrthoperiodic 37 DS-7 SMNUPB SMT200L A acid Example X42 BalanceOrthoperiodic 37 200CT DS-1 IRA900J DS-2 A acid Example X43 BalanceOrthoperiodic 37 200CT DS-1 IRA900J DS-5 A acid Example X44 BalanceOrthoperiodic 37 200CT DS-1 IRA900J DS-6 A acid Example X45 BalanceOrthoperiodic 37 200CT DS-1 IRA900J SA10AOH A acid Example X46 BalanceOrthoperiodic 37 200CT DS-4 IRA900J DS-2 A acid

TABLE 3 Formulation of aqueous solution Ion exchange method pH Periodicacids adjuster MethodA1 Method A2 Method A3 Water Content Content Mixedresin Acidic cation exchange resin Basic anion exchange resin Chelatingresin Membranous ion exchanger Step Content Type (% by mass) Type (% bymass) 1 2 3 1 2 1 2 1 1 2 B Example X47 Balance Orthoperiodic 37 200CTDS-4 IRA900J DS-5 A acid Example X48 Balance Orthoperiodic 37 200CT DS-4IRA900J DS-6 A acid Example X49 Balance Orthoperiodic 37 200CT DS-4IRA900J SA10AOH A acid Example X50 Balance Orthoperiodic 37 200CT SK1BHIRA900J DS-2 A acid Example X51 Balance Orthoperiodic 37 200CT SK1BHIRA900J DS-5 A acid Example X52 Balance Orthoperiodic 37 200CT SK1BHIRA900J DS-6 A acid Example X53 Balance Orthoperiodic 37 200CT SK1BHIRA900J SA10AOH A acid Example X54 Balance Orthoperiodic 37 200CT SK1BHIRA900J SA10AOH B acid Example X55 Balance Orthoperiodic 37 MustangPurifier A acid Example X56 Balance Orthoperiodic 37 DS-3 200CT IRA900JA acid Example X57 Balance Orthoperiodic 37 DS-7 200CT IRA900J A acidExample X58 Balance Orthoperiodic 37 DS-10 200CT IRA900J A acid ExampleX59 Balance Orthoperiodic 37 SMNUPB 200CT IRA900J A acid Example X60Balance Orthoperiodic 37 SMT100L 200CT IRA900J A acid Example X61Balance Orthoperiodic 37 SMT200L 200CT IRA900J A acid Example X62Balance Orthoperiodic 37 DS-3 DS-4 DS-5 A acid Example X63 BalanceOrthoperiodic 37 DS-7 DS-4 DS-5 A acid Example X64 Balance Orthoperiodic37 DS-10 DS-4 DS-5 A acid Example X65 Balance Orthoperiodic 37 SMNUPBDS-4 DS-5 A acid Example X66 Balance Orthoperiodic 37 SMT100L DS-4 DS-5A acid Example X67 Balance Orthoperiodic 37 SMT200L DS-4 DS-5 A acidExample X68 Balance Orthoperiodic 37 DS-3 SK1BH DS-2 A acid Example X69Balance Orthoperiodic 37 DS-7 SK1BH DS-2 A acid

TABLE 4 Ion exchange method Formulation of aqueous solution Method A2 pHAcidic Basic Periodic acids adjuster cation anion Method A3 ContentContent Method A1 exchange exchange Chelating Membranous Water (% by (%by Mixed resin resin resin resin ion exchanger Step Content Type mass )Type mass) 1 2 3 1 2 1 2 1 1 2 B Example Balance Orthoperiodic 37 DS-10SK1BH DS-2 A X70 acid Example Balance Orthoperiodic 37 SMNUPB SK1BH DS-2A X71 acid Example Balance Orthoperiodic 37 SMT100L SK1BH DS-2 A X72acid Example Balance Orthoperiodic 37 SMT200L SK1BH DS-2 A X73 acidExample Balance Orthoperiodic 37 DS-3 Mustang Purifier A X74 acidExample Balance Orthoperiodic 37 DS-7 Mustang Purifier A X75 acidExample Balance Orthoperiodic 37 DS-10 Mustang Purifier A X76 acidExample Balance Orthoperiodic 37 SMNUPB Mustang Purifier A X77 acidExample Balance Orthoperiodic 37 SMT100L Mustang Purifier A X78 acidExample Balance Orthoperiodic 37 SMT200L Mustang Purifier A X79 acidExample Balance Orthoperiodic 37 DS-3 DS-7 Mustang A X80 acid ExampleBalance Orthoperiodic 37 DS-3 DS-10 Mustang A X81 acid Example BalanceOrthoperiodic 37 DS-7 DS-10 Mustang A X82 acid Example BalanceOrthoperiodic 37 SMNUPB SMT100L Mustang A X83 acid Example BalanceOrthoperiodic 37 SMNUPB SMT200L Mustang A X84 acid Example BalanceOrthoperiodic 37 SMT100L SMT200L Mustang A X85 acid Example BalanceOrthoperiodic 37 DS-3 DS-7 Mustang A X86 acid Example BalanceOrthoperiodic 37 DS-3 DS-10 Mustang A X87 acid Example BalanceOrthoperiodic 37 DS-7 DS-10 Mustang A X88 acid Example BalanceOrthoperiodic 37 SMNUPB SMT100L Mustang A X89 acid Example BalanceOrthoperiodic 37 SMNUPB SMT200L Mustang A X90 acid Example BalanceOrthoperiodic 37 SMT100L SMT200L Mustang A X91 acid Example BalanceOrthoperiodic 37 DS-3 DS-7 Purifier A X92 acid

TABLE 5 Ion exchange method Formulation of aqueous solution Method A2 pHAcidic Basic Method A3 Periodic acids adjuster cation anion MembranousContent Content Method A1 exchange exchange Chelating ion Water (% by (%by Mixed resin resin resin resin exchanger Step Content Type mass) Typemass) 1 2 3 1 2 1 2 1 1 2 B Example Balance Orthoperiodic 37 DS-3 DS-10Purifier A X93 acid Example Balance Orthoperiodic 37 DS-7 DS-10 PurifierA X94 acid Example Balance Orthoperiodic 37 SMNUPB SMT100L Purifier AX95 acid Example Balance Orthoperiodic 37 SMNUPB SMT200L Purifier A X96acid Example Balance Orthoperiodic 37 SMT100L SMT200L Purifier A X97acid Example Balance Orthoperiodic 37 DS-3 DS-7 Purifier A X98 acidExample Balance Orthoperiodic 37 DS-3 DS-10 Purifier A X99 acid ExampleBalance Orthoperiodic 37 DS-7 DS-10 Purifier A X100 acid Example BalanceOrthoperiodic 37 SMNUPB SMT100L Purifier A X101 acid Example BalanceOrthoperiodic 37 SMNUPB SMT200L Purifier A X102 acid Example BalanceOrthoperiodic 37 SMT100L SMT200L Purifier A X103 acid Example BalanceOrthoperiodic 37 200CT IRA900J Mustang A X104 acid Example BalanceOrthoperiodic 37 DS-4 DS-5 Mustang A X105 acid Example BalanceOrthoperiodic 37 SK1BH DS-2 Mustang A X106 acid Example BalanceOrthoperiodic 37 200CT IRA900J Purifier A X107 acid Example BalanceOrthoperiodic 37 DS-4 DS-5 Purifier A X108 acid Example BalanceOrthoperiodic 37 SK1BH DS-2 Purifier A X109 acid Example BalanceOrthoperiodic 37 200CT IRA900J Mustang Purifier A X110 acid ExampleBalance Orthoperiodic 37 DS-4 DS-5 Mustang Purifier A X111 acid ExampleBalance Orthoperiodic 37 SK1BH DS-2 Mustang Purifier A X112 acid ExampleBalance Orthoperiodic 37 DS-10 DS-4 DS-5 Mustang A X113 acid ExampleBalance Orthoperiodic 37 SMNUPB SK1BH DS-2 Mustang A X114 acid ExampleBalance Orthoperiodic  5 DS-7 DS-10 A X115 acid

TABLE 6 Formulation of aqueous solution Ion exchange method pH Method A2Periodic acids adjuster Method A1 Acidic cation Water Content ContentMixed resin exchange resin Content Type (% by mass) Type (% by mass) 1 23 1 Example XI16 Balance Orthoperiodic  5 TEAH Adjusted DS-7 DS-10 acidExample X117 Balance Orthoperiodic  5 TEAH Adjusted DS-7 DS-4 acidExample X118 Balance Orthoperiodic  5 TEAH Adjusted DS-7 acid ExampleX119 Balance Orthoperiodic  5 TEAH Adjusted SMNUPB SMT100L acid ExampleX120 Balance Orthoperiodic  5 TEAH Adjusted SMNUPB DS-4 acid ExampleX121 Balance Orthoperiodic  5 TEAH Adjusted SMNUPB acid Example X122Balance Orthoperiodic  5 TMAH Adjusted DS-7 DS-10 acid Example X123Balance Orthoperiodic  5 TBAH Adjusted DS-7 DS-10 acid Example X124Balance Orthoperiodic  5 DBU Adjustec DS-7 DS-10 acid ComparativeBalance Orthoperiodic 37 Example X1 acid Comparative BalanceOrthoperiodic 37 Example X2 acid Comparative Balance Orthoperiodic 37DS-7 SMNUPB SMT200L 200CT Example X3 acid Ion exchange method Method A2Method A3 Acidic cation Basic anion Chelating Membranous ion exchangeresin exchange resin resin exchanger Step 2 1 2 1 1 2 B Example XI16 AExample X117 DS-5 A Example X118 Mustang A Example X119 A Example X120DS-5 A Example X121 Mustang A Example X122 A Example X123 A Example X124A Comparative A Example X1 Comparative B Example X2 Comparative SK1BHIRA900J SA10AOH Mustang Purifier A Example X3

TABLE 7 Formulation of aqueous solution Overview of test pH NumberNumber Number of Number of Periodic acids adjuster of kinds of kinds ofkinds of Content Content of ion kinds of non- membranous PurificationWater (% by (% by exchange mixed mixed ion pH effect Content Type mass)Type mass) methods resins resins exchangers Step B adjuster Ti ZrExample X1 Balance Orthoperiodic 37 1 1 0 0 A B D D acid Example X2Balance Orthoperiodic 37 1 1 0 0 A B D D acid Example X3 BalanceOrthoperiodic 37 1 1 0 0 A B D D acid Example X4 Balance Orthoperiodic37 1 1 0 0 A B D D acid Example X5 Balance Orthoperiodic 37 1 1 0 0 A BD D acid Example X6 Balance Orthoperiodic 37 1 1 0 0 A B D D acidExample X7 Balance Orthoperiodic 37 1 0 1 0 A B D D acid Example X8Balance Orthoperiodic 37 1 0 1 0 A B D D acid Example X9 BalanceOrthoperiodic 37 1 0 1 0 A B D D acid Example X10 Balance Orthoperiodic37 1 0 1 0 A B D D acid Example X11 Balance Orthoperiodic 37 1 0 1 0 A BD D acid Example X12 Balance Orthoperiodic 37 1 0 1 0 A B D D acidExample X13 Balance Orthoperiodic 37 1 0 1 0 A B D D acid Example X14Balance Orthoperiodic 37 1 0 1 0 A B D D acid Example X15 BalanceOrthoperiodic 37 1 0 1 0 A B D D acid Example X16 Balance Orthoperiodic37 1 0 1 0 A B D D acid Example X17 Balance Orthoperiodic 37 1 0 1 0 A BD D acid Example X18 Balance Orthoperiodic 37 1 0 1 0 A B D D acidExample X19 Balance Orthoperiodic 37 1 0 1 0 A B D D acid Example X20Balance Orthoperiodic 37 1 0 1 0 A B D D acid Example X21 BalanceOrthoperiodic 37 1 0 1 0 A B D D acid Example X22 Balance Orthoperiodic37 1 0 1 0 A B D D acid Example X23 Balance Orthoperiodic 37 1 0 1 0 A BD D acid Example X24 Balance Orthoperiodic 37 1 0 1 0 A B D D acidExample X25 Balance Orthoperiodic 37 1 0 1 0 A B D D acid Example X26Balance Orthoperiodic 37 1 0 1 0 A B C C acid Example X27 BalanceOrthoperiodic 37 1 0 1 0 A B C C acid Example X28 Balance Orthoperiodic37 1 0 1 0 A B C C acid Example X29 Balance Orthoperiodic 37 1 0 0 1 A BD D acid Example X30 Balance Orthoperiodic 37 1 0 0 1 A B D D acid

TABLE 8 Formulation of aqueous solution Overview of test pH NumberNumber Number Number of Periodic acids adjuster of kinds of of kindskinds of Content Content of ion kinds of of non- membranous PurificationWater (% by (% by exchange mixed mixed ion Step pH effect Content Typemass) Type mass) methods resins resins exchangers B adjuster Ti ZrExample Balance Orthoperiodic 37 1 2 0 0 A B C C X31 acid ExampleBalance Orthoperiodic 37 1 2 0 0 A B C C X32 acid Example BalanceOrthoperiodic 37 1 2 0 0 A B C C X33 acid Example Balance Orthoperiodic37 1 2 0 0 B B C C X34 acid Example Balance Orthoperiodic 37 1 2 0 0 A BC C X35 acid Example Balance Orthoperiodic 37 1 2 0 0 A B C C X36 acidExample Balance Orthoperiodic 37 1 2 0 0 A B C C X37 acid ExampleBalance Orthoperiodic 37 1 3 0 0 A B B B X38 acid Example BalanceOrthoperiodic 37 1 3 0 0 A B B B X39 acid Example Balance Orthoperiodic37 1 3 0 0 A B B B X40 acid Example Balance Orthoperiodic 37 1 3 0 0 A BB B X41 acid Example Balance Orthoperiodic 37 1 0 2 0 A B C C X42 acidExample Balance Orthoperiodic 37 1 0 2 0 A B C C X43 acid ExampleBalance Orthoperiodic 37 1 0 2 0 A B C C X44 acid Example BalanceOrthoperiodic 37 1 0 2 0 A B C C X45 acid Example Balance Orthoperiodic37 1 0 2 0 A B C C X46 acid Example Balance Orthoperiodic 37 1 0 2 0 A BC C X47 acid Example Balance Orthoperiodic 37 1 0 2 0 A B C C X48 acidExample Balance Orthoperiodic 37 1 0 2 0 A B C C X49 acid ExampleBalance Orthoperiodic 37 1 0 2 0 A B C C X50 acid Example BalanceOrthoperiodic 37 1 0 2 0 A B C C X51 acid Example Balance Orthoperiodic37 1 0 2 0 A B C C X52 acid Example Balance Orthoperiodic 37 1 0 2 0 A BC C X53 acid Example Balance Orthoperiodic 37 1 0 2 0 B B C C X54 acidExample Balance Orthoperiodic 37 1 0 0 2 A B C C X55 acid ExampleBalance Orthoperiodic 37 2 1 1 0 A B C C X56 acid Example BalanceOrthoperiodic 37 2 1 1 0 A B C C X57 acid Example Balance Orthoperiodic37 2 1 1 0 A B C C X58 acid Example Balance Orthoperiodic 37 2 1 1 0 A BC C X59 acid Example Balance Orthoperiodic 37 2 1 1 0 A B C C X60 acid

TABLE 9 Overview of test Formulation of aqueous solution Number pHNumber Number of Number of Periodic acids adjuster of kinds of kindskinds of Content Content of ion kinds of of non- membranous PurificationWater (% by (% by exchange mixed mixed ion Step pH effect Content Typemass) Type mass) methods resins resins exchangers B adjuster Ti ZrExample Balance Orthoperiodic 37 2 1 1 0 A B C C X61 acid ExampleBalance Orthoperiodic 37 2 1 1 0 A B C C X62 acid Example BalanceOrthoperiodic 37 2 1 1 0 A B C C X63 acid Example Balance Orthoperiodic37 2 1 1 0 A B C C X64 acid Example Balance Orthoperiodic 37 2 1 1 0 A BC C X65 acid Example Balance Orthoperiodic 37 2 1 1 0 A B C C X66 acidExample Balance Orthoperiodic 37 2 1 1 0 A B C C X67 acid ExampleBalance Orthoperiodic 37 2 1 1 0 A B C C X68 acid Example BalanceOrthoperiodic 37 2 1 1 0 A B C C X69 acid Example Balance Orthoperiodic37 2 1 1 0 A B C C X70 acid Example Balance Orthoperiodic 37 2 1 1 0 A BC C X71 acid Example Balance Orthoperiodic 37 2 1 1 0 A B C C X72 acidExample Balance Orthoperiodic 37 2 1 1 0 A B C C X73 acid ExampleBalance Orthoperiodic 37 2 1 0 2 A B B B X74 acid Example BalanceOrthoperiodic 37 2 1 0 2 A B B B X75 acid Example Balance Orthoperiodic37 2 1 0 2 A B B B X76 acid Example Balance Orthoperiodic 37 2 1 0 2 A BB B X77 acid Example Balance Orthoperiodic 37 2 1 0 2 A B B B X78 acidExample Balance Orthoperiodic 37 2 1 0 2 A B B B X79 acid ExampleBalance Orthoperiodic 37 2 2 0 1 A B B B X80 acid Example BalanceOrthoperiodic 37 2 2 0 1 A B B B X81 acid Example Balance Orthoperiodic37 2 2 0 1 A B B B X82 acid Example Balance Orthoperiodic 37 2 2 0 1 A BB B X83 acid Example Balance Orthoperiodic 37 2 2 0 1 A B B B X84 acidExample Balance Orthoperiodic 37 2 2 0 1 A B B B X85 acid ExampleBalance Orthoperiodic 37 2 2 0 1 A B B B X86 acid Example BalanceOrthoperiodic 37 2 2 0 1 A B B B X87 acid Example Balance Orthoperiodic37 2 2 0 1 A B B B X88 acid Example Balance Orthoperiodic 37 2 2 0 1 A BB B X89 acid Example Balance Orthoperiodic 37 2 2 0 1 A B B B X90 acid

TABLE 10 Formulation of aqueous solution Overview of test pH NumberNumber Number Number of Periodic acids adjuster of kinds of of kindskinds of Content Content of ion kinds of of non- membranous PurificationWater (% by (% by exchange mixed mixed ion Step pH effect Content Typemass) Type mass) methods resins resins exchangers B adjuster Ti ZrExample Balance Orthoperiodic 37 2 2 0 1 A B B B X91 acid ExampleBalance Orthoperiodic 37 2 2 0 1 A B B B X92 acid Example BalanceOrthoperiodic 37 2 2 0 1 A B B B X93 acid Example Balance Orthoperiodic37 2 2 0 1 A B B B X94 acid Example Balance Orthoperiodic 37 2 2 0 1 A BB B X95 acid Example Balance Orthoperiodic 37 2 2 0 1 A B B B X96 acidExample Balance Orthoperiodic 37 2 2 0 1 A B B B X97 acid ExampleBalance Orthoperiodic 37 2 2 0 1 A B B B X98 acid Example BalanceOrthoperiodic 37 2 2 0 1 A B B B X99 acid Example Balance Orthoperiodic37 2 2 0 1 A B B B X100 acid Example Balance Orthoperiodic 37 2 2 0 1 AB B B X101 acid Example Balance Orthoperiodic 37 2 2 0 1 A B B B X102acid Example Balance Orthoperiodic 37 2 2 0 1 A B B B X103 acid ExampleBalance Orthoperiodic 37 2 0 1 1 A B C C X104 acid Example BalanceOrthoperiodic 37 2 0 1 1 A B C C X105 acid Example Balance Orthoperiodic37 2 0 1 1 A B C C X106 acid Example Balance Orthoperiodic 37 2 0 1 1 AB C C X107 acid Example Balance Orthoperiodic 37 2 0 1 1 A B C C X108acid Example Balance Orthoperiodic 37 2 0 1 1 A B C C X109 acid ExampleBalance Orthoperiodic 37 2 0 1 2 A B B B X110 acid Example BalanceOrthoperiodic 37 2 0 1 2 A B B B X111 acid Example Balance Orthoperiodic37 2 0 1 2 A B B B X112 acid Example Balance Orthoperiodic 37 3 1 1 1 AB A A X113 acid Example Balance Orthoperiodic 37 3 1 1 1 A B A A X114acid Example Balance Orthoperiodic  5 1 2 0 0 A B C C X115 acid ExampleBalance Orthoperiodic  5 TEAH Adjusted 1 2 0 0 A A B B X116 acid ExampleBalance Orthoperiodic  5 TEAH Adjusted 2 1 1 0 A A B B X117 acid ExampleBalance Orthoperiodic  5 TEAH Adjusted 2 1 0 1 A A B B X118 acid ExampleBalance Orthoperiodic  5 TEAH Adjusted 1 2 0 0 A A B B X119 acid ExampleBalance Orthoperiodic  5 TEAH Adjusted 2 1 1 0 A A B B X120 acid

TABLE 11 Overview of test Formulation of aqueous solution Number NumberpH Number Number of of Periodic acids adjuster of kinds of kinds kindsof Content Content of ion kinds of of non- membranous Purification Water(% by (% by exchange mixed mixed ion Step pH effect Content Type mass)Type mass) methods resins resins exchangers B adjuster Ti Zr ExampleBalance Ortho-  5 TEAH Adjusted 2 1 0 1 A A B B X121 periodic acidExample Balance Ortho-  5 TMAH Adjusted 1 2 0 0 A A B B X122 periodicacid Example Balance Ortho-  5 TBAH Adjusted 1 2 0 0 A A B B X123periodic acid Example Balance Ortho-  5 DBU Adjusted 1 2 0 0 A A B BX124 periodic acid Comparative Balance Ortho- 37 0 0 0 0 A B F F ExampleX1 periodic acid Comparative Balance Ortho- 37 0 0 0 0 B B F F ExampleX2 periodic acid Comparative Balance Ortho- 37 3 3 2 2 A B — — ExampleX3 periodic acid

From the results shown in Table 2, it has been confirmed that by themanufacturing method according to the embodiment of the presentinvention, the chemical solution according to the embodiment of thepresent invention can be efficiently obtained.

In addition, it has been confirmed that the greater the number ofrequirements satisfied among (i) application of a plurality of kinds ofmethods among the methods A1 to A3, (ii) use of a plurality of mixedresins at the time of applying the method A1 (use of the method A12),(iii) use of a plurality of cation exchange resins and a plurality ofanion exchange resins at the time of applying the method A2 (applicationof the method A22), (iv) use of a plurality of membranous ion exchangersat the time of applying the step A3 (application of the method A32), and(V) use of a chelating resin at the time of applying the method A2, thebetter the purification effect (the results of Examples X1 to X114 andthe like).

It has been confirmed that in a case where all of the methods A1 to A3are performed in the case of (i) application of a plurality of kinds ofmethods among the methods A1 to A3, the purification effect is furtherimproved (results of Examples X113 and X114 and the like).

It has been confirmed that in a case where three or more mixed resinsare used in the case of (ii) application of the method A12, thepurification effect is further improved (the results of Examples X38 toX41 and the like).

Furthermore, it has been confirmed that in a case where the aqueoussolution to be treated includes a pH adjuster, the purification effectis further improved (the results of Examples X115 to X124).

Example Y

[Preparation of Chemical Solution]

<Raw Materials>

The chemical solutions used in examples and comparative examples wereprepared using the following raw materials.

(Water)

-   -   Water: ultrapure water (ultrapure water manufactured by an        ultrapure water manufacturing device “PURELAB Ultra”        (manufactured by ORGANO CORPORATION))

(Periodic Acids)

-   -   Orthoperiodic acid: reagent A (orthoperiodic acid including Ti        and Zr)    -   Orthoperiodic acid: reagent B (orthoperiodic acid including Ti)    -   Orthoperiodic acid: reagent C (orthoperiodic acid including Zr)

(pH Adjuster)

-   -   TMAH: Tetramethylammonium hydroxide    -   TEAH: Tetraethylammonium hydroxide    -   TBAH: Tetrabutylammonium hydroxide    -   DBU: diazabicycloundecene

All the pH adjusters described above were classified as a semiconductorgrade.

(Source of Ammonium Ions)

-   -   NH₃ ⁺: aqueous ammonia (semiconductor grade)

(Source of Anionic Species)

-   -   I⁻: hydrogen iodide    -   I₃ ⁻: ammonium triiodide    -   IO₃ ⁻: iodic acid    -   Br⁻: hydrogen bromide    -   Cl⁻: hydrochloric acid    -   NO₃ ⁻: nitric acid    -   Sulfate ion: sulfuric acid    -   Sulfite ion: sulfite    -   Phosphate ion: phosphoric acid    -   Phosphite ion: phosphorous acid

All the sources of anionic species described above are all classified asa semiconductor grade.

[Preparation of Chemical Solution]

Example Y3

The aqueous solution was treated (ion exchange method) in the samemanner as in Example X1, thereby obtaining a chemical solution havingthe formulation shown in Table 3.

Example Y6

A chemical solution was prepared according to the same procedure as inExample Y3, except that the filtration (step B) was not performed.

Example Y9

The aqueous solution was treated (ion exchange method) in the samemanner as in Example X31, thereby obtaining a chemical solution havingthe formulation shown in Table 3.

Example Y12

The aqueous solution was treated (ion exchange method) in the samemanner as in Example X80, thereby obtaining a chemical solution havingthe formulation shown in Table 3.

Example Y15

The aqueous solution was treated (ion exchange method) in the samemanner as in Example X115, thereby obtaining a chemical solution havingthe formulation shown in Table 3.

Examples Y16 to Y27

A chemical solution was prepared according to the same procedure as inExample Y15, except that a pH adjuster was added to the aqueous solutionto be treated such that the pH of the obtained chemical solution becamethe value shown in Table 3.

Examples Y28 to Y30

Chemical solutions were prepared according to the same procedure as inExample Y9, except that a source of ammonium ions or a source of anionicspecies was added to the aqueous solution to be treated such that theobtained chemical solutions had the formulation shown in Table 3.

Examples Y1, Y2, Y4, Y5, Y7, Y8, Y10, Y11, Y13, and Y14

A chemical solution of Example Y1 was prepared according to the sameprocedure as in Example Y3, except that the reagent B was used insteadof the reagent A. A chemical solution of Example Y2 was preparedaccording to the same procedure as in Example Y3, except that thereagent C was used instead of the reagent A.

Likewise, chemical solutions of Examples Y4, Y5, Y7, Y8, Y10, Y11, Y13,and Y14 were prepared according to the same procedure as in Examples Y6,Y9, Y12, or Y15, except that the reagent B or the reagent C was usedinstead of the reagent A.

Comparative Example Y1

Orthoperiodic acid (reagent A) was dissolved in water, and the obtainedaqueous solution was filtered by the same method as that described inExample X without being subjected to the treatment method using an ionexchange method, thereby obtaining a chemical solution of ComparativeExample Y1.

Comparative Example Y2

Orthoperiodic acid (reagent A) was dissolved in water, and the obtainedaqueous solution was used as a chemical solution of Comparative ExampleY2.

Comparative Example Y3

The aqueous solution obtained by being treated by the same method asthat in Comparative Example X3 was used as a chemical solution ofComparative Example Y3.

Comparative Examples Y4 and Y5

A chemical solution of Comparative Example Y4 was prepared according tothe same procedure as in Comparative Example Y1, except that the reagentB was used instead of the reagent A. A chemical solution of ComparativeExample Y5 was prepared according to the same procedure as inComparative Example Y1, except that the reagent C was used instead ofthe reagent A.

The content of Ti and Zn in each chemical solution was checked by thesame method (ICP-MS) as that described in Example X.

The content of the above components in each chemical solution is asshown in Table 3. In Table 3, the components not descried in the fieldsof each chemical solution are components that are not included in thechemical solution.

The content of anionic species and ammonium ions was checked by ionchromatography (using DIONEX ICS-2100 manufactured by Thermo FisherScientific Inc.).

[Test and Evaluation]

<Ru Etching Performance>

Substrates were prepared in which a ruthenium layer was formed on onesurface of a commercial silicon wafer (diameter: 12 inches) by achemical vapor deposition (CVD) method.

Each of the obtained substrates was put in a container filled with thechemical solution of each of the examples or comparative examples, andthe chemical solution was stirred for 0.5 minutes to perform a rutheniumlayer removal treatment. The temperature of the chemical solution was25° C.

From the difference in the thickness of the ruthenium layer before andafter the treatment, the etching rate of the chemical solution forruthenium was calculated and evaluated based on the following standard.

-   -   A: equal to or higher than 600 Å/min    -   B: equal to or higher than 300 Å/min and less than 600 Å/min    -   C: equal to or higher than 50 Å/min and less than 300 Å/min    -   D: less than 50 Å/min

<Co Etching Performance and W Etching Performance>

For cobalt and tungsten, the etching performance was evaluated using thesame method and standard as those used for evaluating the Ru etchingperformance.

<Residual Metal Inhibition Properties>

The chemical solution of each of the examples and comparative exampleswas sprayed for 1 minute on a silicon wafer having a diameter of 300 mmat a flow rate of 1.5 L/min. Then, water was sprayed for 1 minute on thesilicon water at a flow rate of 1.5 L/min, and finally, a nitrogen gaswas sprayed on the silicon wafer at a flow rate of 50 L/min.

Thereafter, the surface of the silicon wafer was measured by ElectronSpectroscopy for Chemical Analysis (ESCA, device name: PHI QuanteraSXMTM), and the concentration of residual metal atoms on the surface ofthe silicon wafer (atoms/cm²) was measured and evaluated according tothe following standard.

According to this evaluation, the better the residual metal inhibitionproperties of the chemical solution, the better the defect inhibitionperformance of the chemical solution.

-   -   A: less than 1×10⁷ atoms/cm²    -   B: equal to or higher than 1×10⁷ atoms/cm² and less than 1×10⁸        atoms/cm²    -   C: equal to or higher than 1×10⁸ atoms/cm² and less than 1×10⁹        atoms/cm²    -   D: equal to or higher than 1×10⁹ atoms/cm² and less than 1×10¹⁰        atoms/cm²    -   E: equal to or higher than 1×10¹⁰ atoms/cm²

<Smoothness (Roughness)>

With reference to the method for evaluating Ru etching performancedescribed above, a ruthenium layer removal treatment was performed on asubstrate on which a ruthenium layer having a thickness of 15 nm wasformed. At a point in time when the removal treatment had been performedfor half of the time required for the ruthenium layer to disappear, theremoval treatment was stopped, the surface of the ruthenium layer wasobserved with a scanning electron microscope, and the smoothness of theportion to be treated was evaluated based on the following standard.

-   -   A: The surface of the ruthenium layer is smooth and has no        roughness.    -   B: The surface of the ruthenium layer is rough, but the        roughness is at an acceptable Level.

<Amount of Particles>

The amount of particles in the chemical solution was measured using aparticle counter (KS-42A manufactured by RION Co., Ltd.), and the amountof particles in the chemical solution was evaluated based on to thefollowing standard.

-   -   A: Substantially no particles are present in the chemical        solution.    -   B: There are many particles in the chemical solution, although        the amount thereof is at an acceptable level.

The following Table 3 shows the test conditions and results.

In Table 3, ppm, ppb, and ppt described as units mean ppm by mass, ppbby mass, and ppt by mass respectively.

In Table 3, the field of “Content” in the fields of “Metal component”and “Ammonium ions and anionic species” shows the content (mass ratio)of each component with respect to the total mass of the periodic acids.

In Table 3, the field of “Filtration” shows whether or not the aqueoussolution treated by the ion exchange method was further subjected tofiltration (the step B). A means that filtration (step B) was performed,and B means that filtration (step B) was not performed.

In Table 3, the description of “Balance” in the field of “Content” for“Water” shows that the rest of the components other than water describedin the table is water.

In Table 3, the description of “Adjusted” in the field of “Content” for“pH adjuster” shows that the chemical solution includes a pH adjuster insuch an amount that the chemical solution had a predetermined pH (4.0,6.0, or 9.0).

There was no change in the content of orthoperiodic acid in the aqueoussolution before and after performing various purification treatments.For example, in the aqueous solution which was used for preparingExample Y3 and obtained by the same treatment as that in Example X1, thecontent of orthoperiodic acid in the aqueous solution with respect tothe total mass of the aqueous solution remained at 37% by mass beforeand after the treatment.

Furthermore, in Examples Y16 to Y27, the pH of the aqueous solution didnot change before and after the purification treatment was performed onthe aqueous solution to which various pH adjusters were added.

TABLE 12 Ammonium Evaluation Periodic acids ions or Residual Content pHpH of anionic metal Etching Etching Etching Amount Water (% by adjusterchemical Metal component species Step inhibition performance performanceperformance Smooth- of Content Type mass Type Content solution TypeContent Type Content Type Content B properties for Ru for Co for W nessparticles Example Balance Orthoperiodic 37 1.0 Ti 100 ppb A D C C C B AY1 acid Example Balance Orthoperiodic 37 1.0 Zr 100 ppb A D C C C B A Y2acid Example Balance Orthoperiodic 37 1.0 Ti 100 ppb Zr 100 ppb A D C CC B A Y3 acid Example Balance Orthoperiodic 37 1.0 Ti 100 ppb B D C C CB B Y4 acid Example Balance Orthoperiodic 37 1.0 Zr 100 ppb B D C C C BB Y5 acid Example Balance Orthoperiodic 37 1.0 Ti 100 ppb Zr 100 ppb B DC C C B B Y6 acid Example Balance Orthoperiodic 37 1.0 Ti  10 ppb A C CC C B A Y7 acid Example Balance Orthoperiodic 37 1.0 Zr  10 ppb A C C CC B A Y8 acid Example Balance Orthoperiodic 37 1.0 Ti  10 ppb Zr  10 ppbA C C C C B A Y9 acid Example Balance Orthoperiodic 37 1.0 Ti  1 ppb A BC C C B A Y10 acid Example Balance Orthoperiodic 37 1.0 Zr  1 ppb A B CC C B A Y11 acid Example Balance Orthoperiodic 37 1.0 Ti  1 ppb Zr  1ppb A B C C C B A Y12 acid Example Balance Orthoperiodic  5 1.0 Ti  10ppb A C C C C B A Y13 acid Example Balance Orthoperiodic  5 1.0 Zr  10ppb A C C C C B A Y14 acid Example Balance Orthoperiodic  5 1.0 Ti  10ppb Zr  10 ppb A C C C C B A Y15 acid Example Balance Orthoperiodic  5TEAH Adjusted 4.0 Ti  3 ppb Zr  3 ppb A B B B B B A Y16 acid ExampleBalance Orthoperiodic  5 TEAH Adjusted 6.0 Ti  1 ppb Zr  1 ppb A B B B BB A Y17 acid Example Balance Orthoperiodic  5 TEAH Adjusted 9.0 Ti  3ppb Zr  3 ppb A B B B B B A Y18 acid

TABLE 13 Evaluation Periodic acids Residual Etching Etching EtchingContent pH pH of Ammonium ions or metal per- per- per- Amount Water (%by adjuster chemical Metal component anionic species Step inhibitionformance formance formance Smooth- of Content Type mass Type Contentsolution Type Content Type Content Type Content B properties for Ru forCo for W ness particles Example Balance Orthoperiodic  5 TMAH Adjusted4.0 Ti  3 ppb Zr  3 ppb A B B B B B A Y19 acid Example BalanceOrthoperiodic  5 TMAH Adjusted 6.0 Ti  1 ppb Zr  1 ppb A B B B B B A Y20acid Example Balance Orthoperiodic  5 TMAH Adjusted 9.0 Ti  3 ppb Zr  3ppb A B B B B B A Y21 acid Example Balance Orthoperiodic  5 TBAHAdjusted 4.0 Ti  3 ppb Zr  3 ppb A B B B B B A Y22 acid Example BalanceOrthoperiodic  5 TBAH Adjusted 6.0 Ti  1 ppb Zr  1 ppb A B B B B B A Y23acid Example Balance Orthoperiodic  5 TBAH Adjusted 9.0 Ti  3 ppb Zr  3ppb A B B B B B A Y24 acid Example Balance Orthoperiodic  5 DBU Adjusted4.0 Ti  3 ppb Zr  3 ppb A B B B B B A Y25 acid Example BalanceOrthoperiodic  5 DBU Adjusted 6.0 Ti  1 ppb Zr  1 ppb A B B B B B A Y26acid Example Balance Orthoperiodic  5 DBU Adjusted 9.0 Ti  3 ppb Zr  3ppb A B B B B B A Y27 acid Example Balance Orthoperiodic 37 1.0 Ti  10ppb Zr 10 ppb NH4⁺ 1 A C A A A B A Y28 acid ppm Example BalanceOrthoperiodic 37 1.0 Ti  10 ppb Zr 10 ppb I⁻, I₃ ⁻, IO₃ ⁻, 1 A C C C C AA Y29 acid Br⁻, Cl⁻, ppm NO₃ ⁻, sulfate ion, sulfite ion, phosphate ion,phosphite ion Example Balance Orthoperiodic 37 1.0 Ti  10 ppb Zr  10 ppbIO₃ ⁻ 1 A C C C C A A Y30 acid ppm Comparative Balance Orthoperiodic 371.0 Ti 200 ppm Zr 200 ppm A E B B B B A Example Y1 acid ComparativeBalance Orthoperiodic 37 1.0 Ti 200 ppm Zr 200 ppm B E B B B B B ExampleY2 acid Comparative Balance Orthoperiodic 37 1.0 Ti  0.1 ppt Zr  0.1 pptA A D D D B A Example Y3 acid Comparative Balance Orthoperiodic 37 1.0Ti 200 ppm A E B B B B A Example Y4 acid Comparative BalanceOrthoperiodic 37 Zr 200 ppm A E B B B B A Example Y5 acid

From the results shown in Table 3, it has been confirmed that thechemical solution according to the embodiment of the present inventiondemonstrates excellent etching performance for transitionmetal-containing substances and has excellent defect inhibitionperformance.

It has been confirmed that in a case where the chemical solutionincludes a predetermined amount of NH₄ ⁺, the chemical solutiondemonstrates further improved etching performance for transitionmetal-containing substances (result of Example Y28).

It has been confirmed that in a case where the chemical solutionincludes a predetermined amount of anionic species, the portion to betreated exhibits better smoothness after the etching treatment (theresults of Examples Y29 and Y30).

It has been confirmed that in a case where filtration is performed inaddition to the ion exchange method performed on the aqueous solution asa substance to be purified in the method for manufacturing a chemicalsolution according to the embodiment of the present invention, theamount of particles in the obtained chemical solution can be reduced(the results of Examples Y4 to Y6).

It has been confirmed that in a case where the chemical solutionincludes a pH adjuster, the etching performance for various transitionmetal-containing substances is further improved (the results of ExamplesY15 to Y27). Furthermore, it has been confirmed that such a chemicalsolution can also be obtained by adding a pH adjuster to the aqueoussolution as a substance to be purified (step C) before performing theion exchange method in the method for manufacturing a chemical solutionaccording to the embodiment of the present invention.

It has been confirmed that in a case where the pH of the chemicalsolution is 4.0 to 9.0, the etching performance for transitionmetal-containing substances is further improved (the results of ExamplesY15 to Y27).

It has been confirmed that in view of further improving the residualmetal inhibition properties (defect inhibition properties), the contentof all of the first metal component in the chemical solution withrespect to the total mass of the periodic acids is more preferably equalto or smaller than 10 ppb by mass, and even more preferably equal to orsmaller than 5 ppb by mass (the results of Examples Y1 to Y15).

Example Z

By using a chemical solution, a test was performed to evaluate whetherthe chemical solution is suitable for simultaneously removing two ormore kinds of transition metal-containing substances on a substrate.

[Preparation of Chemical Solution]

An aqueous solution (substance to be purified) including periodic acidor the like was treated, thereby obtaining a chemical solution to beused in Example Z.

The raw materials used for preparing the aqueous solution are asfollows.

-   -   Water: ultrapure water (ultrapure water manufactured by an        ultrapure water manufacturing device “PURELAB Ultra”        (manufactured by ORGANO CORPORATION))    -   Orthoperiodic acid: reagent A (orthoperiodic acid including Ti        and Zr)

(pH Adjuster)

-   -   TMAH: Tetramethylammonium hydroxide    -   TEAH: Tetraethylammonium hydroxide    -   KOH: potassium hydroxide    -   (C₂H₅)₃N(OH)CH₃: triethylmethylammonium hydroxide    -   (C₃H₇)₂N(OH)(CH₃)₂: dimethyldipropylammonium hydroxide    -   HNO₃: nitric acid

All the pH adjusters used were classified as a semiconductor grade.

(Carboxylic Acid Compound)

-   -   DTPA: Diethylene Triamine Pentaacetic Acid    -   Citric acid    -   Phthalic acid (ortho form)    -   Oxalic acid    -   Acetic acid    -   Glycolic acid

(Water-Soluble Organic Solvent)

-   -   DEGEE: Diethylene glycol diethyl ether

(Preparation of Aqueous Solution (Substance to be Purified))

The aforementioned orthoperiodic acid and a pH adjuster, which is usedas desired, were dissolved in water, thereby preparing an aqueoussolution.

(Preparation of chemical solution)

Thereafter, the aqueous solution was subjected to a treatment by an ionexchange method and a filtration treatment (Step B) with reference toExample X, and either or both of a water-soluble organic solvent and acarboxylic acid compound were added thereto as desired, therebyobtaining a chemical solution having the formulation shown in Table 4.

In Table 4, the content of Ti and Zr in each chemical solution was theamount corresponding to “C” in the evaluation standard for the contentof Ti and Zr shown in Example X.

In Table 4, the description of “Balance” in the field of “Content” for“Water” shows that the rest of the components other than water describedin the table is water.

The description of “Adjusted” in the field of “Content” for “pHadjuster” shows that the chemical solution includes a pH adjuster insuch an amount that the chemical solution had a predetermined pH.

[Test and Evaluation]

(Evaluation of Etching Performance (Etching Rate))

A wafer with a film having a Ru film or a Cu film was immersed for 10minutes in a chemical solution at the temperature shown in Table 4, thenrinsed with water, and dried over nitrogen.

Before and after the treatment, the change in the thickness of the Rufilm or Cu film on the wafer was measured by a four-terminal method, andthe etching rate of the chemical solution for Ru or Cu was calculated.

The Ru film of the wafer used for the evaluation is a Ru film formed bya physical vapor deposition (PVD) method, and the Cu film is a Cu filmformed by an electrolytic plating (ECD) method.

(Evaluation of Surface Properties (Cu Surface Oxidation) of Portion tobe Treated)

After the evaluation of the etching rate, the Cu film of the wafer witha Cu film was visually observed to investigate whether or not the Cufilm was discolored before and after the treatment. In a case where theCu film is found to be discolored, the surface has been oxidized, andthe surface properties of the portion to be treated are poor. Theresults of the visual observation were evaluated according to thefollowing standard.

-   -   A: No discoloration (oxidation) has occurred on the Cu film.    -   B: Although the Cu film has been slightly discolored (oxidized),        the wafer can be put to practical use.    -   C: The Cu film has been discolored (oxidized), and the wafer is        problematic for practical use.

(Simultaneous Removal of Cu and Ru)

A patterned wafer was prepared which had an interlayer insulating filmhaving a groove, TiN having a film thickness of 3 nm (barrier metallayer) disposed along the inner wall of the groove, Ru having a filmthickness of 3 nm (liner layer) disposed along the inside of the TiN,and Cu (wiring, line width: 45 nm) filling up the inside of the Ru.

The patterned wafer was immersed in a chemical solution at thetemperature shown in Table 4, thereby removing Cu on the patterned waferby 15 nm from the wafer surface. Thereafter, a rinsing treatment wasperformed by immersing the wafer for 1 minute in a 1% by mass aqueouscitric acid solution (rinsing solution) at 25° C.

Flatness of Cu

The treated wafer was observed with a scanning electron microscope(SEM), and evaluated according to the following standard.

-   -   A: The surface roughness of Cu (wiring) does not increase before        and after etching.    -   B: Although the surface roughness of Cu (wiring) slightly        increases before and after etching, the wafer can be put to        practical use.    -   C: The surface roughness of Cu (wiring) increases before and        after etching, and the wafer is problematic for practical use.

Removal of Ru

The treated patterned wafer was observed with a transmission electronmicroscope (TEM) so as to check whether Ru (liner layer) was removedtogether with Cu (wiring). In a case where Ru was removed, the wafer wasevaluated as OK, and in a case where Ru was not removed, the wafer wasevaluated as NG.

Table 4 shows the results.

TABLE 14 Composition of chemical solution Carboxylic acid Water-solubleChemical agent compound organic solvent Evaluation result Content pHContent Content pH of Processing Etching rate Surface (% by adjuster (%by (% by Ti Zr Water chemical temperature (Å/min) oxidation FlatnessRemoval Type mass) Type Content Type mass) Type mass) Content ContentContent solution (° C.) Ru Cu of Cu of Cu of Ru Example Z1 H₅IO₆ 2.0TMAH Adjusted C C Balance 8.5 22  63 106 A A OK Example Z2 H₅IO₆ 2.0TMAH Adjusted C C Balance 8.5 40 112 123 A A OK Example Z3 H₅IO₆ 2.0TEAH Adjusted C C Balance 8.5 22  57 100 A A OK Example Z4 H₅IO₆ 2.0 KOHAdjusted C C Balance 8.5 30  88  79 B B OK Example Z5 H₅IO₆ 1.0 TMAHAdjusted C C Balance 8.5 50 133  89 B B OK Example Z6 H₅IO₆ 2.0 TMAHAdjusted C C Balance 8.5 50 212 106 A A OK Example Z7 H₅IO₆ 3.0 TMAHAdjusted C C Balance 8.5 50 350 127 A A OK Example Z8 H₅IO₆ 3.0 TMAHAdjusted C C Balance 9.0 50  77  78 A A OK Example Z9 H₅IO₆ 6.0 TMAHAdjusted C C Balance 7.5 50 312 432 A A OK Example Z10 H₅IO₆ 6.0 TMAHAdjusted C C Balance 8.0 50 317 193 A A OK Example Z11 H₅IO₆ 6.0 TMAHAdjusted C C Balance 8.5 50 457 154 A A OK Example Z12 H₅IO₆ 6.0 TMAHAdjusted C C Balance 9.0 50 381 154 A A OK Example Z13 H₅IO₆ 6.0 TMAHAdjusted C C Balance 9.5 50 111 101 A A OK Example Z14 H₅IO₆ 6.0 TMAHAdjusted C C Balance 10.1  50  65  83 A A OK Example Z15 H₅IO₆ 6.0 TMAHAdjusted C C Balance 10.8  50  51  69 A A OK Example Z16 H₅IO₆ 1.0 TEAHAdjusted C C Balance 8.9 60  66  62 B B OK Example Z17 H₅IO₆ 1.0 TEAHAdjusted C C Balance 3.4 22  85  60 B B OK Example Z18 H₅IO₆ 1.0 TEAHAdjusted C C Balance 6.8 22  75  61 B B OK Example Z19 H₅IO₆ 3.0(C₂H₅)₃N(OH)CH₃ Adjusted C C Balance 9.4 60  55  57 A A OK Example Z20H₅IO₆ 3.0 (C₃H₇)₂N(OH)(CH₃)₂ Adjusted C C Balance 9.8 60  57  60 A A OKExample Z21 H₅IO₆ 2.0 TMAH Adjusted DTPA 0.1 DEGDEE 10.0 C C Balance 8.522  65 111 A A OK Example Z22 H₅IO₆ 2.0 TMAH Adjusted Citric acid 0.1DEGDEE 10.0 C C Balance 8.5 40 130 150 A A OK Example Z23 H₅IO₆ 2.0 TEAHAdjusted Phthalic acid 0.5 C C Balance 8.5 22  63 103 A A OK Example Z24H₅IO₆ 2.0 TMAH Adjusted Oxalic acid 0.1 DEGDEE 10.0 C C Balance 8.5 30 88  79 A A OK Example Z25 H₅IO₆ 2.0 TMAH Adjusted Phthalic acid 0.5 C CBalance 8.5 40 142 126 A A OK Example Z26 H₅IO₆ 2.0 TMAH Adjusted Citricacid 0.5 C C Balance 8.5 40 110 131 A A OK Example Z27 H₅IO₆ 2.0 TMAHTMAH Oxalic acid 0.5 C C Balance 8.5 40  76 142 A A OK Example Z28 H₅IO₆2.0 TMAH TMAH Acetic acid 0.5 C C Balance 8.5 40 208 144 A A OK ExampleZ29 H₅IO₆ 2.0 TMAH Adjusted Glycolic acid 0.5 C C Balance 8.5 40 123 173A A OK

From the results shown in Table 4, it has been confirmed that thechemical solution according to the embodiment of the present inventionis also suitable for being used to simultaneously remove two or morekinds of transition metal-containing substances (particularly, aCu-containing substance and a Ru-containing substance).

It has been confirmed that in a case where the content of periodic acidsis 4% to 40% by mass with respect to the total mass of the chemicalsolution, the etching performance is further improved (comparisonbetween Examples Z7 and Z11 and the like).

It has been confirmed that in a case where the pH adjuster is aquaternary ammonium salt compound, the flatness of the portion to betreated is further improved (comparison between Examples Z3 and Z4 andthe like).

(Evaluation of Rinsing Solution)

The patterned wafer was subjected to the same treatment as the treatmentof simultaneously removing Cu and Ru in Example Z11, except that therinsing solution was changed to 1% by mass hydrochloric acid or 1% bymass aqueous ammonia.

The treated patterned wafer was observed with SEM, and the result of therinsing treatment was evaluated according to the following standard.

-   -   A: No residue is found.    -   B: Residues derived from Cu are found in a portion of the        lateral wall of the barrier metal layer.    -   C: Residues derived from Cu are found on the lateral wall of the        barrier metal layer and in a portion of Cu (wiring).    -   D: Residues derived from Cu are found on the lateral wall of the        barrier metal layer and in the entire Cu (wiring).

The results of the evaluation will be shown below.

Example Rinsing solution Evaluation Example Z11 1% by mass aqueouscitric acid solution A Example Z11-2 1% by mass hydrochloric acid BExample Z11-3 1% by mass aqueous TMAH solution C

In Examples Z11, Z11-2, and Z11-3, all of the evaluation results of“Flatness of Cu” and “Removal of Ru” were the same.

From the results described above, it has been confirmed that the rinsingsolution is preferably an acidic rinsing solution, and more preferablyan aqueous citric acid solution.

In addition, by using the chemical solutions of Example Z, the sameevaluation as the evaluation of residual metal inhibition properties inExample Y was carried out. As a result, all of the chemical solutionsattained grades equal to or higher than D.

EXPLANATION OF REFERENCES

-   -   10 a: wiring substrate not yet being subjected to recess etching        treatment for wiring    -   10 b: wiring substrate having undergone recess etching treatment        for wiring    -   12: interlayer insulating film    -   14: barrier metal layer    -   16: transition metal-containing wiring    -   18: recess portion    -   20, 30: object to be treated    -   22: substrate    -   24: transition metal-containing film    -   26: outer edge portion

What is claimed is:
 1. A method for manufacturing a chemical solution,comprising: a step A of performing an ion exchange method on a substanceto be purified, which includes one or more kinds of periodic acidsselected from the group consisting of a periodic acid and a saltthereof, one or more kinds of first metal components selected from thegroup consisting of Ti and Zr, and water, so as to obtain the chemicalsolution, wherein the chemical solution comprising: one or more kinds ofperiodic acids selected from the group consisting of a periodic acid anda salt thereof; one or more kinds of first metal components selectedfrom the group consisting of Ti and Zr; and water, in a case where thechemical solution includes one kind of first metal component, a contentof the one kind of first metal component is 1 ppt by mass to 100 ppm bymass with respect to a total mass of the periodic acids in the chemicalsolution, and in a case where the chemical solution includes two kindsof first metal components, a content of both the two kinds of firstmetal components is equal to or smaller than 100 ppm by mass withrespect to the total mass of the periodic acids in the chemicalsolution, and a content of at least one of the two kinds of first metalcomponents is equal to or greater than 1 ppt by mass with respect to thetotal mass of the periodic acids in the chemical solution.
 2. The methodfor manufacturing a chemical solution according to claim 1, wherein in acase where the chemical solution includes one kind of first metalcomponent, a content of the one kind of first metal component is 1 ppbby mass to 100 ppb by mass with respect to the total mass of theperiodic acids in the chemical solution, and in a case where thechemical solution includes two kinds of first metal components, a totalcontent of both the two kinds of first metal components is equal to orsmaller than 100 ppb by mass with respect to the total mass of theperiodic acids in the chemical solution, and a content of at least oneof the two kinds of first metal components is equal to or greater than 1ppb by mass with respect to the total mass of the periodic acids in thechemical solution.